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Momentum or tne syste ¢, , Objective Questions, , Multiple Choice Questions, , 1, The resultant force acting on a body is, , zero, then, , (a) body is in unequilibrium, , (b) body is in equilibrium, , (c] body moves with constant acceleration, (d)body moves with retardation, , 2. A force cannot change the speed of a, , moving object., (a) True (b) False, (c} Can't say (d) Partially true/false, , 3, If an unbalanced force is applied on the, moving object there will be a change in, a orin the............ ofits motion., (a) shape, speed (b) speed, direction, (c) shape, direction (d)size, direction, , 4, When a rubber balloon held between, the hands is pressed, its shape changes., This happens because, (a) balanced forces act on the balloon, (b) unbalanced forces act on the balloon, (c) frictional forces act on the balloon, , (d) gravitational forces act on the balloon

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Force and Laws of Motion, , _—, , §. The inertia of an object tends to cause, the object (NCERT Exemplar), {a)to increase its speed, (b) to decrease its speed, , (c)to resist any change in its state of motion, (d) to decelerate due to friction, , 6. The inertia of a moving object depends, on, (a) momentum of the object, (b) speed of the object, (c)mass of the object, (d) shape of the object, , 7. Dirty blanket is beaten by stick to, remove dust particles. Which law holds, good for this?, , (a) Law of conservation of momentum, (b) Law of inertia, , (c) Law of impulse, , (cd) Law of canservation of energy, , 8. A heavy objects will have more inertia, than lighter one., (a) True, (b) False, (c) Can't say, (d) Partially true/false, , 9, Father has mass 60 kg and the mass of, his son is 30 kg. The ratio of the inertia, , of the father to his child is, (a) 1:1 (b)1:2, (c) 2:1 (d)1:3, , 10. An object of mass 2 kg is sliding with a, constant velocity of 4ms“ ona, frictionless horizontal table. The force, required to keep the object moving with, , the same velocity is. (NCERT Exemplar), (a) 32N (b) ON, (c) 2N (d) BN, , 11. A water tanker filled upto 2 of its height is, , moving with a uniform speed: On sudden, application of the brake, the water in the, tank would be (NCERT Exemplar), , 79, , (a) move backward, , (b) move f, (c)be unaffected ove tonware, , (d) rise upwards, 12. What is the SI unit of momentum?, (a) kg-ms, , (b) msik, (c)kg-ms~' 9, , (d)kg/ms, , 13. The quantity of motion in a body i, also known as .........00. ; —, (a)Momentum, (c) Speed, , (b) Velocity, (a) Acceleration, , 14. An object of mass 4 kg moves with a, velocity of 4 m/s, then its momentum, will be, (a)16 m/s, (c) 16 kg-m/s, , (b) 4 m/s, (d)4 ka-m/s, , 15. A faster moving body has greater, momentum than a slower one, irrespective of their masses., {a)True, (b) False, (c) Can't say, (d) Partially true/false, , 16. What will be the percentage change in, momentum of a body when both its, , mass and velocity are doubled?, , (a)400 (b) 75, (c)500 ({d)300, 17. 1 dyne is equal to, (a)10* N {b)10" N, (c}i0“* N (go N, 18. One Newton is defined as the force ., which gives a mass of 1 kg and, acceleration of ......... ‘i, (a)] km/h (b) 1 m/s, (c) 1 km/h? (d)1 mis?, , 19. Two forces are acting on a body in, different directions, then acceleration, produced in the body is due to, {a)resultant of both forces, (b) sum of both forces, (c) difference of both forces, (d) None of the above

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CBSE New Pattern ~ Science Ix (Term,, 'y), , , , 80, , 20. What is the numerical formula for force?, , (a)F =mo (oiF=2, a, , (c)F =ma’ (a)F =a'm, , 21. A goalkeeper in a game of football pulls, his hands backwards after holding the, ball shot at the goal. This enables the, goalkeeper to (NCERT Exemplar), (a) exert larger force on the ball, {b) reduce the time far which force is exerted, , by the ball on hands, (c} increase the rate of change of momentum, (d} decrease the rate of change of momentum, , 22. A student is able to move a block of, mass 2 kg with minimum force of 1 N., The force of friction between the object, and the surface will be, (aj2N (b)0.9N, (c}IN (d)ON, , 23. A force acts on a body of mass 5 kg and, changes its velocity from 8 m/s to, 12 m/s in 4 s, then magnitude of force is, (a)8N (b)4N, (c)5N (d)6N, , 24, A truck moving with a speed of, 54 km/h. Truck driver applied brakes, , suddenly and brings the truck to rest in, 5 s, then the average retarding force on, truck, if mass of the truck and driver is, 400 kg, will be, (a) 1200 N (b) 600 N, (c)800 N (0) 500N, , 25. Two foi -es F, and F, are acting on a, body as shown in the figure, then, acceleration in the body is, , =5, [m= 500} aN, , (b)3 m/s?, (d)22 mis”, , n I with Column IT and, riate option from the, , , , ————, F,=50N, , {a]23 m/s", (c)2 mis, , 26. Match Colum, , choose approp’, codes given low., , Column Colma tt, ‘A. Change in Lo okg, momentum, eee ah, Cc Force _ 3. kg-ms*, D Mas 4 Ns, , , , Codes, , A Bc O, (3 4 1 2, (b)4 1 2 3, ()4 3 2 1, {1 2 3 4, , 27. When a moving body comes to rest,, then its initial velocity is taken as zero., , (a)True (b} False, (c}Can't say (d) Partially true/false, , 28. A bus of mass 500 kg is moving with a, velocity of 5 m/s and is acted upon by a, forward force of 500 N due to engine and, retarding force of 200 N due to friction., Velocity of bus after 20 s will be, (a) 15 m/s (b}17 més, (c)19 mis (d) 21 mis, , 29. A bullet of 20 g strikes a sand bag ata, speed of 200 m/s and gets embedded, after travelling 2 cm, then the resistive, force exerted by sand on the bullet is, (a}2x10°N (b)2x10°N, (c)2x10°N (d)2x10°N, , 30, When a person jumps down from &, tower into a stretched trapaulin, then he, receives, (a) greater injury, (c) no injury, , 31. According to the third law of motion,, action and reaction (CERT Exempla ?, (a) always act on the seme body, {b) always act on different bodies in opposite, directions, {c) have same magnitude and dire, {d) act on either body at normal to €a, , {b) less injury, (d} None of these, , ction, eh other

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‘orce and Laws of Motio', ; — 81, 92. It is possible to walk if and only if third Codes, law of motion holds true. ABC OD, {a) True fal3 4 1 2, (b) False (b)4 1 2 3, {c)Cant say {c)1 2 3 4, {d) Partially true/false 2 4 1 3, 33. Consider two spring balances hooked 37. Rocket works on the principle of, as shown in the figure below. We pull conservation of ———_(NCERT Exemplar), them in opposite directions. If the {almass (b) energy, reading shown by A is 1.5 N, then (c)momentum (d) velocity, reading shown by B will be 38. The linear momentum of a system, fas HERD remains constant if nO ......... force acts, A 8 on it., (a}.5N (b)2.5N (a)internal (b) external, (c)3.0N {d}zero (c)Both(a)and(b) (d) None of these, 34, Water sprinkler used for grass lawn 39. A body at rest explodes into two equal, ins to rotate as soon as the water is parts. Then, they move with, supplied. Identify the principle on (a) different speeds in different directions, which it works. (b) different speeds in same direction, , (a) Newton's first law of motion, , {b) Newton's second law of motion, , {c) Newton's third law of motion, , {d) Newton's universal law of gravitation, , 35. Shock absorbers are provided in the, vehicles to smooth out shock impulses, which obeys Newton’s first law., , (a) True, (b) False, , (c) Can't say, (d) Partially true/false, , 36. Match the column J with column II and, , , , choose the appropriate option from, codes given below., _ Column} —_ Column, ‘A. Recoil of gun 1. Newton's 2nd, scecsemcesnapecsona en, B. Ineria _2. 10° gems", C. Momentum 3, Newton's 3rd, , _ law of motion, D. 1 kg-ms™ 4. Newton's Ist law, , _of motion’, , {c) same speed in same direction, {d)same speed in opposite directions, , 40. The law in which the sum of product of, masses and velocities of two moving, bodies before and after their collision, remains constant is known as law of, conservation of mass., , (a) True {b) False, (c) Can't say (d) Partially true/false, , 41. Two objects of masses 1 kg and 2 kg are, moving with velocities 2 m/s and 4 m/s,, respectively. They collide and after, collision the first object moves at a, velocity 3 m/s, then velocity of second, , object is, , (a)3.5 m/s (b}4.5 mis, , {c}2.5 m/s (d)O mis, 42. A bullet of mass 30 g is fired, , horizontally with a velocity of 120 m/s, from a pistol of mass 2 kg, the recoil, velocity of the pistol is, (a}1.8 mis, , {c}2.4 ms, , (b) 2.8 m/s, (d)1.8 mis