Question 1 :
A solid disc of mass {tex} M {/tex} is just held in air horizontally by throwing {tex} 40 \ stones \ per \ sec {/tex} vertically upwards to strike the disc each with a velocity {tex} 6 \mathrm { ms } ^ { - 1 } {/tex}. If the mass of each stone is {tex} 0.05 \mathrm { kg } {/tex} what is the mass of the disc {tex} \left( g = 10 \mathrm { ms } ^ { - 2 } \right) {/tex}
Question 2 :
A man of weight {tex} 75 \mathrm { kg } {/tex} is standing in an elevator which is moving with an acceleration of {tex} 5 \mathrm { m } / \mathrm { s } ^ { 2 } {/tex} in upward direction the apparent weight of the man will be {tex} \left( g = 10 \mathrm { m } / \mathrm { s } ^ { 2 } \right) {/tex}
Question 3 :
A block of 10 kg is pulled by a constant speed on a rough horizontal surface by a force of 19.6 N. The coefficient of friction is
Question 4 : A bar of mass <em>m</em><sub>1</sub> is placed on a plank of mass <em>m</em><sub>2</sub>, which rests on a smooth horizontal plane. The coefficient of friction between the surfaces of bar and plank is <em>k</em>. The plank is subjected to a horizontal force <em>F</em> depending on time <em>t</em> as <em>F</em> = <em>at</em>, where <em>a</em> is a constant. The moment of time <em>t</em><sub>0</sub> at which the plank starts sliding is<img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c1091da6d070c2abf8ff"/>
Question 5 :
Two bodies of mass 1 kg and 2 kg move towards each other in mutually perpendicular direction with the velocities 3 m/s and 2 m/s respectively. If the bodies stick together after collision the energy loss will be
Question 7 :
A block of mass {tex} 5 \mathrm { kg } {/tex} is on a rough horizontal surface and is at rest. Now a force of {tex} 24 \mathrm { N } {/tex} is imparted to it with negligible impulse. If the coefficient of kinetic friction is 0.4 and {tex} g = 9.8 \mathrm { m } / \mathrm { s } ^ { 2 } , {/tex} then the acceleration of the block is
Question 8 :
The resultant of two forces, one double the other in magnitude, is perpendicular to the smaller of the two forces. The angle between the two forces is
Question 9 :
A 20-kg crate is lifted by an upward force of 200 N. The crate's upward acceleration is -
Question 10 :
A player caught a cricket ball of mass 150 g moving at a rate of 20 m/s. If the catching process is completed in 0.1s, the force of the blow exerted by the ball on the hand of the player is equal to [2006]
Question 11 :
A block of metal weighting 2 kg is resting on a frictionless plane. It is stuck by a jet releasing water at a rate of 1 kg/sec and at a speed of 5 m/s. The initial acceleration of the block will be
Question 12 : A ball <em>A</em> of mass 2<em>m</em> is kept at rest on a smooth horizontal surface. Another ball <em>B</em> of same size and having mass <em>m</em> moving with velocity <em>v</em>, collides with ball <em>A</em>. If during collision an impulse <em>J</em> = <em>mv</em> is imparted to the ball <em>A</em> by the ball <em>B</em> then coefficient of restitution between the balls is<img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c20df1a5a149feab9a12"/>
Question 13 : Three blocks of masses m<sub>1</sub>, m<sub>2</sub> and m<sub>3</sub> are placed on a horizontal frictionless surface. A force of 40 N pulls the system then calculate the value of T, if m<sub>1</sub> = 10kg, m<sub>2</sub> = 6 kg, m<sub>3</sub> = 4 kg - <br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75ececb5f89758f2d4f4f6' height='53' width='187' >
Question 14 : The coefficient of friction between two surfaces is μ = 0.8. The tension in the string shown in the figure is - <br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75f13b491ec9580069869d' height='99' width='126' >
Question 15 : A 9 kg block is originally at rest on a horizontal smooth surface. If a horizontal force <em>F</em> is applied such that it varies with time as shown in figure, the speed of block in 4 s is <br> <img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c1dfbfef6349df00fe0a"/>
Question 16 : In the arrangement, shown in figure, pulleys are massless and frictionless and threads are inextensible. Blocks of mass <em>m</em><sub>1</sub> will remain at rest if <br> <img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c10d4bec8070e4e15032"/>
Question 17 :
If a force of {tex} 250 \mathrm { N} {/tex} act on body, the momentum acquired is {tex} 125 \mathrm { kg } {/tex}-{tex} \mathrm { m } / \mathrm { s } {/tex}. What is the period for which force acts on the body
Question 18 :
A block rests on a rough inclined plame making an angle of {tex} 30 ^ { \circ } {/tex} with the horizontal. The coefficient of static friction between the block and the plane is {tex} 0.8 {/tex}. If the frictional force on the block is {tex} 10\,\mathrm { N } {/tex} , the mass of the block (in {tex} \mathrm { kg } {/tex} ) is<br>{tex} \left.\text { (take } g = 10 \mathrm { m } / \mathrm { s } ^ { 2 } \right) {/tex}<br>
Question 19 : A pearl of mass m is in a position to slide over a smooth wire. At the initial instant the pearl is in the middle of the wire. The wire moves linearly in a horizontal plane with an acceleration a in a direction having angle θ with the wire. The acceleration of the pearl with reference to wire is <br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75eebb4389b1556ddf0778' height='100' width='145' >
Question 20 : A trolley <em>T</em> (mass 5 kg) on a horizontal smooth surface is pulled by a load <em>L</em> (2 kg) through a uniform rope <em>ABC</em> of length 2 m and mass 1 kg. As the load falls from<br/> <em>BC</em> = 0 to <em>BC</em> = 2m, its acceleration (in ms<sup>–2</sup>) changes from (Take <em>g</em> = 10 ms<sup>–2</sup>). <br> <img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c092f1a5a149feab9971"/>
Question 21 :
If a person with a spring balance and a body hanging from it goes up and up in an aeroplane, then the reading of the weight of the body as indicated by the spring balance will
Question 22 :
A lift is moving down with acceleration a. A man in the lift drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift and a man standing stationary on the ground are respectively
Question 23 : In the given arrangement pulleys and string are massless and frictionless and all surfaces are smooth. Find the magnitude of acceleration of wedge of mass <em>M</em>. <br> <img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c10bf1a5a149feab99c3"/>
Question 24 : A body of weight {tex} 50 N {/tex} placed on a horizontal surface is just moved by a force of {tex} 28.2{/tex} {tex} N {/tex}. The frictional force and the normal reaction are<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5dbd66d0e18860128132cd11"><br>
Question 25 :
Two skaters of masses 40 kg and 60 kg respectively stand facing each other at <em>S</em><sub>1</sub> and <em>S</em><sub>2</sub>where <em>S</em><sub>1</sub><em>S</em><sub>2</sub> is 5 m. They pull on a massless rope stretched them, then they meet at
Question 26 : For the system shown in figure, the pulleys are light and frictionless. The tension in the string will be -<br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75eda4491ec9580069854e' height='72' width='137' >
Question 27 : In figure a block of weight 10 N is shown resting on a horizontal surface. The coefficient of static friction between the block and surface is µ<sub>s</sub> = 0.4. A force of 3.5 N will keep the block in uniform motion once it has been set in motion. A horizontal force of 3 N is applied to the block. The block will then - <br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75ee8b4389b1556ddf074d' height='49' width='151' >
Question 28 :
A particle of mass <em>m</em> moving eastward with a speed <em>v</em> collides with another particle of same mass moving northward with same speed <em>v</em>. The two particles coalesce on collision. The new particle of mass 2<em>m</em> will move in the north-east direction with a velocity of
Question 29 :
A box is lying on an inclined plane what is the coefficient of static friction if the box starts sliding when an angle of<br>inclination is {tex} 60 ^ { \circ } {/tex}<br>
Question 30 :
A ball weighing 10g hits a hard surface vertically with a speed of 5 ms<sup>-1</sup> and rebounds with the same speed. The ball remains in contact with the surface for 0.01 s. The average force exerted by the surface on ball is.
Question 31 :
A man slides down a light rope whose breaking strength is <em>η</em> times his weight (<em>η</em> < 1). The maximum acceleration of the man so that the rope just breaks is
Question 32 : Two blocks <em>A</em> and <em>B</em> of equal masses m are suspended with ideal pulley and string arrangement as shown. The acceleration of mass <em>B</em> is <br> <img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c090bfef6349df00fd83"/>
Question 33 :
A ball falls from a height h in a fluid which offers a resistance f = -kv. Find the terminal velocity if mass of the ball is m
Question 34 : Two blocks A and B of masses 6 kg and 3 kg rest on a smooth horizontal surface as shown in fig. If coefficient of friction between A and B is 0.4, the maximum horizontal force which can make them without separation is -<br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75ee88491ec9580069861b' height='87' width='133' >
Question 35 :
Let <em>I</em><sub><em>A</em></sub> and <em>I</em><sub><em>B</em></sub> be moments of inertia of a body about two axes <em>A</em> and <em>B</em> respectively. The axis <em>A</em> passes through the centre of mass of the body but <em>B</em> does not
Question 36 : Two blocks of masses 5 kg and 2 kg are connected by a massless string as shown in figure. A vertical force <em>F</em> is applied on the 5kg block. Find the value of <em>F</em> if tension in the string is 40 N. (<em>g</em> = 10 m/s<sup>2</sup>) <br> <img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c057f1a5a149feab994e"/>
Question 37 :
A glass marble dropped from a certain height above the horizontal surface reaches the surface in time <em>t</em> and then continues to bounce up and down. The time in which the marble finally comes to rest is (coefficient of restitution is <em>e</em>)
Question 39 :
A bullet of mass {tex} 0.1 \mathrm { kg } {/tex} is fired with a speed of {tex} 100 \mathrm { m } / \mathrm { sec } {/tex}, the mass of gun is {tex} 50 \mathrm { kg } {/tex}. The velocity of recoil is
Question 40 : A mass of 2 kg is placed on a trolley of 20 kg sliding on a smooth surface. The coefficient of friction between the mass and surface of trolley is 0.25. A horizontal force of 2N is applied to the mass. The acceleration of the system and the frictional force between the mass and surface of trolley are <br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75ec5a4389b1556ddf0553' height='103' width='196' >
Question 42 :
A wagon weighing {tex} 1000 \mathrm { kg } {/tex} is moving with a velocity {tex} 50 \mathrm { km } / \mathrm { h } {/tex} on smooth horizontal rails. A mass of {tex} 250 \mathrm { kg } {/tex} is dropped into it. The velocity with which it moves now is
Question 43 :
A body takes just twice the time as long to slide down a plane inclined at {tex} 30 ^ { \circ } {/tex} to the horizontal as if the plane were frictionless. The coefficient of friction between the body and the plane is
Question 44 :
A car of mass <em>m</em> is being driven on a circular path of radius <em>R</em>. In which of the following circumstances it will not slip (<font face="Symbol">µ</font> is coefficient of friction between surface and road)
Question 45 :
A boy of {tex} 50 \ kg{/tex} is in a lift moving down with an acceleration {tex} 9.8 \mathrm { ms } ^ { - 2 } . {/tex} The apparent weight of the body is {tex} \left( g = 9.8 \mathrm { ms } ^ { - 2 } \right) {/tex}
Question 46 :
When a body is placed on a rough plane inclined at an angle {tex} \theta {/tex} to the horizontal, its acceleration is
Question 47 : A horizontal force of {tex} 10 N {/tex} is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is {tex} \mathrm 0.2{/tex} . the weight of the block is<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5da9988b3ff4ff5cad668a60"><br>
Question 48 : A block <em>Q</em> of mass <em>M</em> is placed on a horizontal frictionless surface <em>AB</em> and a body <em>P</em> of mass <em>m</em> is released on its frictionless slope. As <em>P</em> slides by a length <em>L</em> on this slope of inclination θ, the block <em>Q</em> would slide by a distance<img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c1efbfef6349df00fe19"/>
Question 49 :
{tex}\mathrm{Assertion}{/tex} : The slope of momentum versus time curve give us the acceleration.<br>{tex}\mathrm{Reason}{/tex} : Acceleration is given by the rate of change of momentum.
Question 50 :
A force of 50 dynes is acted on a body of mass {tex} 5 \mathrm { g } {/tex} which is at rest for an interval of 3 seconds, then impulse is
Question 51 :
A block of mass $2 kg$ is placed on the floor. The coefficient of static friction is $0.4$. Force of $2.8N$ is applied on the block. The force of friction between the block and the floor is (Taken $g = 10m/s^2$)<br/>
Question 52 : Match the following<table class="wysiwyg-table"><tbody><tr><td>List I</td><td>List II</td></tr><tr><td>a. frictional force</td><td>e. reduction of friction</td></tr><tr><td>b. rolling friction</td><td>f. causes wear and tear</td></tr><tr><td>c. ball bearing</td><td>g. less than kinetic friction</td></tr><tr><td>d. trading of surface</td><td>h. increase of friction </td></tr><tr><td><br/></td><td><br/></td></tr></tbody></table>The correct match is
Question 53 :
Assertion: Static friction is a self adjusting force.
Reason: Coefficient of friction does not depend upon mass of the body.
Question 54 :
The coefficient of static friction between contact surfaces of two bodies is $0.5$. The contact surfaces of one body support the other till the inclination is less than(Approximately).
Question 55 :
A boy rolls a rubber ball on a wooden surface. The ball travels a short distance before coming to rest. To make the same ball travel longer distance before coming to rest, he may<br>
Question 56 :
When an axle rotates in a sleeve, the friction involved in the process is
Question 57 :
{tex}\mathrm{Assertion}{/tex} : No force is required by the body to remain in any state. <br>{tex}\mathrm{Reason}{/tex} : In uniform linear motion, acceleration has a finite value.
Question 58 :
If a bullet of mass {tex}5 \ gm{/tex} moving with velocity {tex} 100 \mathrm { m } / \mathrm { sec } {/tex}, penetrates the wooden block upto {tex} 6 \mathrm { cm } {/tex}. Then the average force imposed by the bullet on the block is
Question 59 :
A body rests on a rough horizontal plane. A force is applied to the body directed towards the plane at an angle $\alpha$ with the vertical. The body can be moved along the plane
Question 60 :
You apply a 75-N force to pull a child's wagon across the floor at a constant speed of 0.5 m/s. If you increase your pull to 90 N ,the wagon will
Question 61 :
A person sitting in an open car moving at constant velocity throws a ball vertically up into air. The ball falls
Question 62 : A ball of mass 2.5 kg moving with a velocity of 4 ms<sup>–1</sup> heading towards a wall. The wall is also moving in the same direction with a speed of 1.5 ms<sup>–1</sup> as shown. If coefficient of restitution between ball and wall is 0.4, the speed of ball after collision is<img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c216f1a5a149feab9a1c"/>
Question 63 :
It is easier to roll a barrel full of coal tar than to pull it because
Question 64 :
A car is moving along a straight horizontal road with a speed {tex} v _ { 0 } . {/tex} If the coefficient of friction between the tyres and the road is {tex} \mu , {/tex} the shortest distance in which the car<br>can be stopped is<br>
Question 67 :
Two force, with equal magnitude F, at on a body and the magnitude of the resultant force is $\dfrac{F}{3}$. The angle between the two force is
Question 68 : In the given figure, the mass of block <em>A</em> is 40 kg and of block <em>B</em> is 20 kg. There is no friction at any of the contact surface. Both the systems are held at rest initially. The ratio of acceleration of block <em>B</em> in condition (i) to condition (ii) just at the moment system is released, is <img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c115f1a5a149feab99d0"/>
Question 69 :
A block of mass m is placed at rest on an inclined plane of inclination θ to the horizontal. If the coefficient of friction between the block and the plane is μ, then the total force the inclined plane exerts on the block is-
Question 70 :
To determine the coefficient of friction between a rough surface and a block, the surface is kept inclined at $45^o$ and the block is released from rest. The block takes a time '$t$' in moving a distance '$d$ '.The rough surface is then replaced by a smooth surface and the same experiment is repeated. The block now takes a time '$t/2$' in moving down the same distance '$d$'. The coefficient of friction is
Question 71 : The system shown in the figure is in equilibrium. Masses m<sub>1</sub> and m<sub>2</sub> are 2 kg and 8kg respectively. Spring constants k<sub>1</sub> and k<sub>2</sub> are 50 N/m and 70 N/m respectively. If the compression in second spring is 0.5 m. What is the compression in first spring ? (Both springs have the same natural length) -<br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75ee2cb5f89758f2d4f60e' height='179' width='107' >
Question 72 :
A man weighing $80\ kg$ is standing at the centre of a flat boat and he is $20\ m$ from the shore. He walks $8\ m$ on the boat towards the shore and then halts. The boat weight $200\ kg$. How far is he from the shore at the end of this time?
Question 73 :
The resultant force of {tex} 5 \mathrm { N } {/tex} and {tex} 10 \mathrm { N } {/tex} cannot be
Question 74 :
Eleven forces each equal to $5N$ act on a particle simultaneously. If each force makes an angle $30^\circ$ with the next one, the resultant of all forces is
Question 75 : For the arrangement shown in the Fig. the tension in the string is- [Given: tan<sup>-1</sup> (0.8) = 39<sup>0</sup>] <br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75ee8c491ec9580069861f' height='86' width='112' >
Question 76 :
A light spring balance hangs from the hook of the other light spring balance and a block of mass $M$ kg hangs from the former one. Then the true statement about scale reading is
Question 77 :
A block of mass {tex} 10 \mathrm { kg } {/tex} is placed on a rough horizontal surface having coefficient of friction {tex} \mu = 0.5 . {/tex} If a<br>horizontal force of {tex} 100 N {/tex} is acting on it, then acceleration<br>of the block will be
Question 78 :
A marble block of mass $2kg$ lying on ice when given a velocity of $6m/s$ is stopped by friction in $10s$, then the coefficient of friction is (take g=$10 ms^{-2}$)
Question 79 :
A block of mass $1\ kg$ lies on a horizontal surface in a truck, the coefficient of static friction between the block and the surface is $0.6$. What is the force of friction on the block if the acceleration of the truck is $5\ m/s^{2}$ ?<br>(Take $g=10\ m/s^{2}$)
Question 80 :
A small box resting on one edge of the table is struck in such a way that it slides off the other edge, $1\ m$ away, after $2$ seconds. The coefficient of kinetic friction between the box and the table.<br>
Question 81 :
You and your friend are on ground completely covered with ice with a certain distance apart. Now you throw a ball towards your friend, he catches it and throw back towards you and you catch it and so on. What happens to the distance between you and your friend? (neglect resistance due to ice)
Question 82 :
A car has to move on a level turn of radius $45m$. If the coefficient of static friction between the tyre and the road is $\mu_s = 2.0$, find the maximum speed the car can take without skidding.
Question 83 :
The velocity of a body at time {tex} t = 0 {/tex} is {tex} 10 \sqrt { 2 } \mathrm { m } / \mathrm { s } {/tex} in the north-east direction and it is moving with an acceleration of {tex} 2 \mathrm { m } / \mathrm { s } {/tex} directed towards the south. The magnitude and direction of the velocity of the body after 5 sec will be
Question 84 :
The average depth of indian ocean is about 3000 m. The frictional compression, $\frac { \Delta \mathrm { V } } { \mathrm { V } }$ of work at the bottom of the ocean ( give that the bulk modulus of the water $2.2 \times 10 ^ { 9 }$ $\mathrm { Nm } ^ { - 2 }$ and $g = 10 m s ^ { - 2 }$ is
Question 85 :
Assertion: In order to reduce sliding friction, lubricants are used.
Reason: Lubrication changes the conditions of rubbing, replacing the sliding friction by rolling friction, thereby reducing the force of friction.
Question 86 :
Assertion: When a person walks on a rough surface, the frictional force exerted by surface on the person is opposite to the direction of his motion.
Reason: It is the force exerted by the road on the person that causes the motion.
Question 87 :
Which of the following is used to reduce friction :<br>1. Streamlines<br>2. Use of ball bearings<br>3. Lubrication
Question 88 :
A plumb line is suspended from a ceiling of a car moving with horizontal acceleration of a. What will be the angle of inclination with vertical
Question 89 :
A body of mass 5 kg rests on a rough horizontal surface of coefficient of friction 0.2 . The body is pulled through a distance of {tex} 10 m {/tex} by a horizontal force of {tex} 25 N {/tex}. The kinetic energy acquired by it is {tex} \left( g = 10 \mathrm { ms } ^ { 2 } \right) {/tex}
Question 90 :
A 1.5 kg block is initially at rest on a horizontal frictionless surface when a horizontal force in the positive direction of x-axis is applied to the block. The force is given by $\vec{F} = (4 - x^2)\hat{i}$ N, where x is in meter and the initial position of the block is x=0. The maximum positive displacement x is
Question 91 :
A block of mass $m$ is at rest on a rough inclined plane of angle of inclination $\theta$. If coefficient of friction between the block and the inclined plane is $\mu$, then the minimum value of force along the plane required to move the block on the plane is:
Question 92 : <p> Two point charges + q and -2q are placed at the vertices B and C of an equilateral triangle ABC of side a as given in the figure. Obtain the expression for the direction of the resultant electric field at the vertex A due to these two charges.<br/></p>
Question 93 : Assuming that the block is always remains horizontal, hence the acceleration of B is - <br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75ed9d491ec95800698547' height='144' width='179' >
Question 94 :
The coefficient of static friction between contact surfaces of two bodies is $1$. The contact surfaces of one body support the other till the inclination is less than
Question 95 :
Choose the correct statements. The coefficient of static friction depends on<br/>(1) the material of the bodies in contact.<br/>(2) quality of machining of the surface in contact.<br/>(3) presence of foreign matter between the surface.<br/>(4) area of the surfaces in contact.
Question 96 :
A block is lying on the table. What is the angle between the action of the table and the reaction of the book?
Question 97 :
A horizontal force acting on a box of mass 1$\mathrm { kg }$ has a magnitude of $F = 1 t ^ { 2 } \mathrm { N }$ , where $t$ is in second. If the box starts from rest, determine its speed at$t = 3 \mathrm { s }$ . The coefficient of static friction and kinetic friction between the box and horizontal surface are $\mu _ { s } = 0.4$ and $\mu _ { k } = 0.3$ respectively. $\left( g = 10 \mathrm { m } / \mathrm { s } ^ { 2 } \right)$
Question 98 :
State if the following statements are true or false. Correct the statement if it is false.<br>Tyres of vehicles are provided with grooved designs to decrease friction.
Question 99 :
A block of weight $100$ $N$ is lying on a rough horizontal surface. If coefficient of friction $\cfrac{1}{\sqrt{3}}$. The least possible force that can move the block is
Question 100 :
Which of the following statements is NOT true for friction force?
Question 101 :
A body slipping on a tough horizontal plane moves With a deceleration of 4.0 m/${ s }^{ 2 }$ . What is the coefficient of kinetic friction between the block and the plane ?
Question 102 :
The mass of a lift is 500 kg. When it ascends with an acceleration of {tex} 2 \mathrm { m } / \mathrm { s } ^ { 2 } {/tex}, the tension in the cable will be {tex} \left[ \mathrm { g } = 10 \mathrm { m } / \mathrm { s } ^ { 2 } \right] {/tex}
Question 103 :
A ware house worker exerts a constant horizontal force of magnitude $85\ N$ on a $40kg$ box that is initally at rest on the floor of the ware house. After moving a distance of $2m$ the speed of the box is $1 \ ms^{-1}$. The coefficent of friction between the box and the ware house floor is $(g=10ms^{-2})$
Question 104 :
A body is rolling on the ground with a velocity of $1\ m/s$. After travelling a distance of $5\ m$, the body stops. The coefficient of friction is:
Question 105 :
A body of mass $3\ kg$ is moving along a straight line with a velocity of $24\ {ms}^{-1}$. When it is at appoint $'P'$ a force of $9\ N$ acts on the body in a direction opposite to its motion. The time after which it will be at $'P'$ again is:
Question 106 :
A block of $1\ kg$ is stopped against a wall by applying a force $F$ perpendicular to the wall. If $\mu=0.2$ then minimum value of $F$ will be :
Question 107 :
The upper half of an inclined plane of inclination $\theta$ is perfectly smooth while the lower half is rough $A$ body starting from the rest at top come back to rest at the bottom, then the coefficient of friction for the lower half is given by _______.
Question 108 :
A body of mass 40 gram is moving with a constant velocity of 20 $ms^{-}$ $^{1}$ on a horizontal frictionless table. The force acting on the body in horizontal direction is:
Question 109 : Two trolleys 1 and 2 are moving with acceleration a<sub>1</sub> and a<sub>2</sub> respectively in the same direction. A block of mass 'm' on trolleys 1 is in equilibrium from the frame of observer stationary w.r.t. trolleys 2. The magnitude of friction on block due to trolley is -<br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e75ed85491ec95800698533' height='66' width='206' >
Question 110 :
A stick of {tex} 1 \ m {/tex} is moving with velocity of {tex} 2.7 \times 10 ^ { 8 } \mathrm { ms } ^ { -1 } . {/tex} What is the apparent length of the stick {tex} \left( c = 3 \times 10 ^ { 8 } \mathrm { ms } ^ { - 1 } \right) {/tex}
Question 111 :
A block of mass 2 kg rests on a rough inclned plane making am angle of $30^o$ with the horizontal. The coefficient of static friction between the block and the plans is 0.7. The frictional force on the block is $(g = 9.8 m/s^2)$ :
Question 112 :
A particle attached to a string is rotating with a constant angular velocity and its momentum is $L$. If the string is halved and angular velocity is kept constant, the angular momentum will be
Question 113 :
The limiting value of static friction between two contact surfaces is :
Question 115 :
To avoid slipping while walking on ice, one should take smaller steps because:<br>
