# Physics MCQs Part 7

61, A force of 100 dynes acts for 10 seconds on a body of mass 500g. What is the change in momentum?
A. 100 C.G.S. units
B. 10 C.G.S. units
C. 1000 C.G.S. units
D. 5000 C.G.S. units

62. A rope attached to a post in the ground is pulled horizontally with a force of 80 kg. The pole pulls back with a force of
A. 1000 kg
B. 80 kg
C. 40 kg
D. 160 kg

63. We can clean a dirty carpet by beating. This is in accordance with
A. Newton's first law
B. Newton's second law
C. Newton's third law
D. None of the above

64. A force of 100 dynes acts on a body of 5 gms for 10 secs. What is the velocity produced?
A. 2 fr/sec
B. 20 fr/sec
C. 200 fr/sec
D. 2000 fr/sec

65. Swimming is possible because of which law of motion?
A. Second
B. First
C. Third
D. None of the above

66. A player caught a cricket ball of mass 150 gm. Moving at a rate of 20m/s. If the catching process be completed in 0.1 s. The force of the blow exerted by the ball on the hands is
A. 3000N
B. 300N
C. 30N
D. 30,000N

67. When a body is accelerated,
A. Its velocity always changes
B. Its direction always changes
C. Its speed always changes
D. Its falls towards the earth

68. A force of 150 dynes acts on a mass of 50 gms for 5 seconds. What is the acceleration produced?
A. 4 cms/sec2
B. 9 cms/sec2
C. 10c cms/sec2
D. None of these

69. The action and reaction forces referred in Newton'sthird law of motion
A. Must act upon the same body
B. Must act upon different bodies
C. Need not to be equal in magnitude but must have the same line of action
D. Must be equal in magnitude bu tneed not have the same line of action

70. A force of 100 dynes acts on a body of 5 gms for 10 secs. Find the change in momentum.
A. 10 C.G.. Units
B. 100 C.G.. Units
C. 1000 C.G.. Units
D. 10000 C.G.. Units