Question 1 :
An ice cube is suspended in vacuum in a gravity free hall. As the ice melts it

Question 2 :
A force of 50N is applied on a nail of area 0.001sq.cm. Then the thrust is:

Question 3 :
The mass of the earth is 81 times that of the moon and the radius of the earth is 3.5 times that of the moon. The ratio of the acceleration due to gravity at the surface of the moon to that at the surface of the earth is

Question 4 :
A body of mass $1.5 \ kg$ is dropped from a height of $12 \ m$. What is the force acting on it during its fall? $(g=9.8 \ ms^{-2})$

Question 5 :
$A$ and $B$ are two metallic pieces. They are fully immersed in water and then weighed. Now they show same loss of weight. The conclusion therefore is:<br/>

Question 6 :
A string tied on a roof can bear a maximum tension of $50kg wt$. The minimum acceleration that can be acquired by a man of $98kg$ to descend will be (Take $g=9.8m/{s}^{2}$)

Question 7 :
Equal masses of water and a liquid a relative density $2$ are mixed together, then the mixture has a density (in $g\ cm^{-3}$) of

Question 8 :
Assertion: The pressure at a point is the ratio of force to the area on which force is acting. Reason: Pressure is the thrust acting per unit area.

Question 9 :
The acceleration due to gravity on the surfcae of a planet is one-fourth of the value on Earth. When a brass ball is brought to this planet, its:

Question 10 :
A piece of brass weighs $175g$ in air and $150g$ when fully submerged in water. The density of water is $1.0g&#160; cm^{-3}$.&#160;Why does the brass piece weigh less in water?

Question 12 :
If the mass of earth is $80\ times$ of that of a planet and diameter is double that of planet and $'g'$ on the earth is $9.8\ ms^{-2}$, then the value of $'g'$ on the planet is =_____ $ms^{-2}$

Question 14 :
Two solids A and B Float is a liquid. It is observed that A floats with half its volume immersed and B floats with $2/3$ of its volume immersed. Compare the densities of A and B.

Question 15 :
The radius of earth is about $6400$ km and that of mars is $3200$ km . Thus mars of the earth is about 10 times mass of mars. An object weighs 200 N on the surface of earth. Then its weight on the surface of mars will be

Question 16 :
A solid cube and a solid sphere both made of same material are completely submerged in water but to different depths. The sphere and the cube have same surface area. The buoyant force is<br/>

Question 17 :
For the moon, its mass is $\dfrac{1}{81}$ of earth's mass and its diameter is $\dfrac{1}{3.7}$ of earth's diameter.If acceleration due to gravity of earth surface is $9.8 \ m/s^2$, then at the moon its value is:

Question 19 :
A boat floating in fresh water displaces $16,000\ N$ of water. How many newtons of saltwater would it displace if it floats in saltwater of specific gravity $1.17$?<br>

Question 20 :
If value of acceleration due to gravity changes from one place to another, which of the following force will&#160;undergo a change?

Question 21 :
A pump motor is used to deliver water at a certain rate from a given pipe. To obtain thrice as much water from the same pipe in the same time, power of the motor has to be increased to:

Question 22 :
Three particles of mass $M$ each are placed at corners of an equilateral triangle of side $'d'$ if the sides are increased to $'2d'$ then :

Question 23 :
Mass of a planet is $5 \times &#160;10^{24}$ kg and radius is&#160;$6.1 \times &#160;10^6$m. The energy needed to send a $2$ kg body&#160;into space from its surface, would be.

Question 24 :
Read the assertion and reason carefully to mark&#160;the correct option out of the options given below :Assertion : Generally the path of a projectiel from&#160;the earth is parabolic but it is elliptical&#160;for projectiles going to a very large&#160;height.<br/>Reason : The path of a projectile is independent&#160;of the gravitational force of earth.

Question 25 :
Water flows out horizontally from a hole with a velocity of $20 ms^{-1}$. The area of cross section ofthe hole is 2.5$\times 10^{-3} m^{2}$. Density of water is $1000\ kg m^{-3}$. Power needed to generate kinetic energy from water is

Question 26 :
Number of kilowatt-hours =$\dfrac { volt\times ampere\times time }{ 1000 } $. Then:<br/>

Question 27 :
How many kilograms will a man working at the power of 100 W, be able to lift at<br>constant speed of 1 $m s^{-1}$ vertically ? $(g = 10 m s^{-2})$<br><br><br>

Question 28 :
A motor pump set of efficiency $80\%$, lifts $800$ litres of water in $19.6$ seconds over a head of $20 m$. Its input power is (Take $g=9.8 \ m/s^2$):

Question 29 :
The power of sound from the speaker of a radio is 20 milliwatt. By turning the knob of the volume control the power of the sound is increased to 400 milliwatt . The power increase in decibels as compared to the original power is

Question 30 :
A car of mass 2,000 kg is lifted up a distance of 30 m by a crane in 1 minute. A second crane does the same job in 2 minutes.&#160;The power supplied by second crane is :<br/>

Question 31 :
If the power of a motor is $40kW$, at what speed can it raise a load of $20,000N$?

Question 32 :
A boy of mass $40\ kg$ runs up a flight of $15$ steps each $15\ cm$ high in $10s$.Find the power developed by him: Take $g=10N$ $kg^{-1}$

Question 33 :
Gravitational field is uniform and the gravitational potential difference between surface of a planet and a point $100 m$ above&#160;is $50 J / Kg$. The work done in moving a man $5&#160;kg$ from surface to a point $10 m$ above is :<br/>

Question 35 :
The Jog falls in Karnataka state are nearly $20$ m high. $2000$ tonnes of water falls from it in a minute. Calculate the equivalent power if all this energy can be utilized $(g=10 \:m \:s^{-2})$:<br/>

Question 36 :
An electric iron uses 300 kJ of electrical energy in 2 minutes. What is the rate of power of the electric iron?

Question 37 :
How much water a pump of $2\ kW$ power can raise in one minute to a height of $10\ m$? $(g = 10\ m/s^{2})$

Question 38 :
Write true or false for the following statements:<br>Kilowatt hour is the unit of power.

Question 39 :
On the surface of earth acceleration due to gravity&#160;is g and gravitational potential is V.<br/><table class="wysiwyg-table"><tbody><tr><td>Column-I</td><td>Column-II</td></tr><tr><td>a) At height h = R,&#160;value of g</td><td>(p) decreases by a factor 1/4</td></tr><tr><td>(b) At depth h = R/2&#160;value of g</td><td>(q) decreases by a factor 1/2</td></tr><tr><td>(c) At height h = R,&#160;of V</td><td>(r) Increases by a factor 11/8</td></tr><tr><td>(d) At depth h = R/2&#160;of V&#160;</td><td>(s) Increases by a factor 2<br/>(t) None</td></tr></tbody></table><br/>

Question 40 :
A force applied by the engine of a train of mass $2.05\times 10^{6} kg$ changes its velocity from $5ms_{-1}$ to $25ms^{-1}$ in 5 minutes. The power of the engine