OBJECTIVE QUESTIONS FOR NEET AIIMS JIPMER www wisedane
OBJECTIVE QUESTIONS FOR NEET AIIMS JIPMER www. wisedane. com
PHYSICS WORK ENERGY AND POWER SET 2 MCQ’S
Q 1. Sand particles fall vertically at the rate of 2 kg/s to a conveyor belt moving horizontally with a velocity of 0. 2 m/s, the rate of change of KE is A. 0. 4 J/s B. 0. 08 J/s C. 0. 04 J/s D. 0. 2 J/s
ANSWER(C) EXPLANATION
Q 2. A beed starts sliding from A on a frictionless wire with initial velocity of 4 m/s, figure show on reaching C, its velocity will be A. Zero B. 2 m/s C. 4 m/s D. 8 m/s
ANSWER(D) EXPLANATION
Q 3. A pendulum is swinging in a semi circular path and the maximum speed of the bob at the lowest position is 7 m/s. If g = 9. 8 m/s 2, the length of the pendulum is A. 1 m B. 2. 5 m C. 1. 5 m D. 2. 0 m
ANSWER (B) EXPLANATION
Q 4. The K. E of a 500 gram stone is 100 J. Against a force of 50 N, how long will it travel ? A. 0. 2 s B. 0. 1 s C. 0. 3 s D. 0. 4 s
ANSWER (A) EXPLANATION
Q 5. A body of mass 1 kg falls from rest through a distance of 200 m and acquires a sped of 50 m/s. Work done against friction of air is (take g = 10 m/s 2) A. 700 J B. 12500 J C. 750 J D. 1960 J
ANSWER (C) EXPLANATION
Q 6. A block of mass m slides down along the surface of a bowl (radius R ) from the rim to the bottom. The velocity of the block at the bottom will be :
ANSWER (C) EXPLANATION
Q 7. A block is moved from rest through a distance of 4 m along a st. Line path. The mass of the block is 5 kg and the block be 40 J, at what angle to the path is the force acting ? A. 30 o B. 60 o C. 45 o D. 00
ANSWER (B) EXPLANATION
Q 8. If g is acc. Due to gravity on earth’s surface, the gain in potential energy of an object of mass m raised from surface of earth to a height equal to radius R of earth is
ANSWER (A) EXPLANATION
Q 9. A body of mass 5 kg is moving with a momentum of 10 kg m/s. A force of 0. 2 N acts on it in the direction of motion of body for 10 sec. The increase in its kinetic energy is A. 2. 8 J B. 3. 2 J C. 3. 8 J D. 4. 4 J
ANSWER (D) EXPLANATION
Q 10. A 25 kg crate, starting from rest at the top, slides down a plane that makes an angle of 30 o with the horizontal. When it reaches the bottom of the 10 m long slide, its velocity is 8 m/s. The work done by the force of friction is closest to a value of
ANSWER (D) EXPLANATION
ANSWER (C) EXPLANATION
Q 12. A pump of 200 W power is lifting 2 kg water from an average depth of 10 m per second. Velocity of water delivered by the pump is A. 3 m/s B. 2 m/s C. 4 m/s D. 1 m/s
ANSWER (B) EXPLANATION
Q 13. The power of a water pump is 2 kw. if g = 10 m/s 2, the amount of water it can raise in one minute to a height of 10 m is A. 2000 litre B. 1000 litre C. 100 litre D. 1200 litre
ANSWER (D) EXPLANATION
Q 14. A man is riding on a cycle with velocity 7. 2 km/hr up a hill having a slope 1 in 20. Total mass of the man and cycle is 100 kg. The power of man is : A. 98 W B. 49 W C. 196 W D. 147 W
ANSWER (A) EXPLANATION
Q 15. The force required to row a boat at constant velocity is proportional to the velocity. If it takes 10 horse power to row a certain boat at a speed of 5 km /hr, how much horse power does it take to row it at a speed of 15 km/hr ? A. 90 B. 60 C. 30 D. 180
ANSWER (A) EXPLANATION
Q 16. A 12 HP motor has to be operated 8 hours/day. How much will cost at the rate of 50 paise/K wh in 10 days ? A. Rs. 350/B. Rs- 358/C. Rs- 375/D. Rs- 397/-
ANSWER (B) EXPLANATION
Q 17. A spring of spring constant 8 N/cm has an extension of 5 cm. The minimum work done in joule in increasing the extension from 5 cm to 15 cm is A. 16 J B. 8 J C. 4 J D. 32 J
ANSWER (B) EXPLANATION
Q 18. A spring of spring constant 1000 N/m is compressed through 5 cm and is used to push a metal ball of mass 0. 1 kg. The velocity with which the metal ball moves is A. 5 m/s B. 7. 5 m/s C. 10 m/s D. 2. 5 m/s
ANSWER (A) EXPLANATION
Q 19. The amount of work done in stretching a spring from a stretched length of 10 cm to a stretched length of 20 cm is : A. Equal to the work done in stretching it from 20 cm to 30 cm B. Less than the work done in stretching it from 20 cm to 30 cm C. More than the work done in stretching it from 20 cm to 30 cm D. Equal to the work done in stretching it from 0 cm to 10 cm
ANSWER (B) EXPLANATION
Q 20. The force required to stretch a spring varies with the distance as shown in fig. 5. 4. If the experiment is performed with the above spring of half the length, the line OA will : A. Shift towards F-axis B. Shift towards X-axis C. Remain as it is D. Become double in length
ANSWER (A) EXPLANATION Ø As original length of spring is halved, its extension (x) corresponding to agiven force is halved. Therefore, the line OA shifts towards F axis, Increasing the slope.
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