33 Years NEET-AIPMT Chapterwise Solutions - Physics 2020

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30 NEET-AIPMT Chapterwise Topicwise Solutions Physics
64. A balloon with mass m is descending down with an
acceleration a (where a < g). How much mass should
be removed from it so that it starts moving up with an
acceleration a ?
2ma
(a) (b) 2ma ma ma
(c) (d) (2014)
g + a g − a g + a g − a
65. Three blocks with masses m, 2m and 3m
are connected by strings, as shown in the
figure. After an upward force F is applied
on block m, the masses move upward at
constant speed v.
What is the net force on the block of mass 2m? (g is
the acceleration due to gravity)
(a) 3mg
(b) 6mg
(c) zero (d) 2mg (NEET 2013)
66. A person of mass 60 kg is inside a lift of mass 940 kg
and presses the button on control panel. The lift starts
moving upwards with an acceleration 1.0 m/s 2 . If
g = 10 m s –2 , the tension in the supporting cable is
(a) 8600 N (b) 9680 N
(c) 11000 N (d) 1200 N (2011)
67. The mass of a lift is 2000 kg. When the tension in the
supporting cable is 28000 N, then its acceleration is
(a) 4 m s –2 upwards (b) 4 m s –2 downwards
(c) 14 m s –2 upwards (d) 30 m s –2 downwards
(2009)
68. A block of mass m is placed on a smooth wedge
of inclination q. The whole system is accelerated
horizontally so that the block does not slip on the
wedge. The force exerted by the wedge on the block
will be (g is acceleration due to gravity)
(a) mg cosq (b) mg sinq
(c) mg (d) mg/cosq (2004)
69. A man weighs 80 kg. He stands on a weighing scale
in a lift which is moving upwards with a uniform
acceleration of 5 m/s 2 . What would be the reading
on the scale ? (g = 10 m/s 2 )
(a) zero
(b) 400 N
(c) 800 N (d) 1200 N (2003)
70. A monkey of mass 20 kg is holding a vertical rope.
The rope will not break when a mass of 25 kg is
suspended from it but will break if the mass exceeds
25 kg. What is the maximum acceleration with
which the monkey can climb up along the rope?
(g = 10 m/s 2 )
(a) 5 m/s 2 (b) 10 m/s 2
(c) 25 m/s 2 (d) 2.5 m/s 2 (2003)
71. A lift of mass 1000 kg which is moving with
acceleration of 1 m/s 2 in upward direction, then the
tension developed in string which is connected to
lift is
(a) 9800 N (b) 10,800 N
(c) 11,000 N (d) 10,000 N (2002)
72. Two masses as shown in the figure
are suspended from a massless pulley.
The acceleration of the system when
masses are left free is
(a) 2 g
g
(b)
5g
3
3
g
10g
(c)
(d) g 9
7 (2000)
73. A mass of 1 kg is suspended by a thread. It is
(i) lifted up with an acceleration 4.9 m/s 2 ,
(ii) lowered with an acceleration 4.9 m/s 2 .
The ratio of the tensions is
(a) 1 : 3 (b) 1 : 2 (c) 3 : 1 (d) 2 : 1 (1998)
74. A mass M is placed on a very smooth wedge resting
on a surface without friction.
Once the mass is released, the
acceleration to be given to the
wedge so that M remains at
rest is a where
(a) a is applied to the left and a = g tanq
(b) a is applied to the right and a = g tanq
(c) a is applied to the left and a = g sinq
(d) a is applied to the left and a = g cosq (1998)
75. A monkey is decending from the branch of a tree
with constant acceleration. If the breaking strength
of branch is 75% of the weight of the monkey, the
minimum acceleration with which monkey can slide
down without breaking the branch is
(a) g (b) 3g/4 (c) g/4 (d) g/2 (1993)
ANSWER KEY
1. (c) 2. (c) 3. (b) 4. (c) 5. (c) 6. (b) 7. (b) 8. (c) 9. (d) 10. (b)
11. (b) 12. (c) 13. (c) 14. (b) 15. (d) 16. (d) 17. (c) 18. (a) 19. (c) 20. (c)
21. (a) 22. (a) 23. (d) 24. (a) 25. (d) 26. (a) 27. (c) 28. (b) 29. (a) 30. (a)
31. (d) 32. (c) 33. (d) 34. (d) 35. (a) 36. (c) 37. (a) 38. (a) 39. (c) 40. (d)
41. (d) 42. (b) 43. (a) 44. (d) 45. (b) 46. (a) 47. (b) 48. (d) 49. (d) 50. (d)
51. (c) 52. (c) 53. (b) 54. (d) 55. (c) 56. (c) 57. (b) 58. (a) 59. (c) 60. (b)
61. (c) 62. (d) 63. (a) 64. (a) 65. (c) 66. (c) 67. (a) 68. (d) 69. (d) 70. (d)
71. (b) 72. (b) 73. (c) 74. (a) 75. (c)