Tiêu đề Unit No. 2 Work & Energy Test By Sir Shahid (Google Drive).pdf ✅

www.youtube.com/physicswithshahid WORK & ENERGY (UNIT-2) MDCAT Q1. A weight Whangs from a trolley that runs along a rail. The trolley moves horizontally through a distance p and simultaneously raises the weight through a height q. As a result, the weight moves through a distance r from X to Y. It starts and finishes at rest. How much work is done on the weight during this process? (A) Wp (B) W(p + q) (C) Wq (D) Wr Q2. A constant force of 9.0 kN, parallel to an inclined plane, moves a body of weight 20 kN through a distance of 40 m along the plane at constant speed. The body gains 12 m in height, as shown. How much of the work done is dissipated as heat? (A) 120 kJ (B) 240 kJ (C) 360 kJ (D) 600 kJ Q3. A block of weight W is pulled up a rough slope by a force F. When the block has moved a distance x along the slope, it has risen height h. Which expressions give the amount of work done on the block and the amount of gravitational potential energy gained by the block? Work done Gravitational potential energy A Fx Wh B Fh Wx C Wx Fh D Wh Fx
www.youtube.com/physicswithshahid WORK & ENERGY (UNIT-2) MDCAT Q4. A ball of mass m is thrown up to height h in air with an initial velocity v, as shown. Air resistance is considered negligible. The acceleration of free fall is g. What is the total work done by the gravitational force on the ball during its flight from P to Q? (A) zero (B) 1 2 mv 2 (C) mgh (D) 2mgh Q5. Initially, four identical uniform blocks, each of mass m and thickness h, are spread on a table. The acceleration of free fall is g. How much work is done on the blocks in stacking them on top of one another? (A) 3 mgh (B) 6 mgh (C) 8 mgh (D) 10 mgh Q6. In which situation is work done on an object? (A) The object slides with a constant velocity along a horizontal frictionless surface in a vacuum. (B) A person holds the object at arm's length and at a fixed height above the ground. (C) A person pushes the object up a frictionless ramp. (D) The stationary object floats partially submerged in water. Q7. A car driver adjusts the pressure on a car's brakes so that the car travels at constant speed down a hill from P to Q. The magnitude of the change in the car's kinetic energy is ∆Ek . The magnitude of the change in its gravitational potential energy is ∆Ep. Which statement is correct? (A) ∆Ek > ∆Ep (B) ∆Ek = ∆Ep (C) ∆Ep > ∆Ek > 0 (D) ∆Ek = 0 Q8. A horizontal force of 90 N is used to push a box across a horizontal floor. The frictional force on the box is 50N. What is the gain in kinetic energy of the box when it is moved through a distance of 6.0 m? (A) 240 J (B) 300 J (C) 540 J (D) 840 J
www.youtube.com/physicswithshahid WORK & ENERGY (UNIT-2) MDCAT Q9. A pendulum bob oscillates between P and R. Assuming the gravitational potential energy lost in moving from P to Q is converted into kinetic energy, what is the speed of the bob at Q? (A) √2gx (B) 2gx (C) √2gy (D) 2gy Q10. Which of the following expressions defines power? (A) force x distance moved in the direction of the force (B) force x velocity (C) work done + time taken (D) work done x time taken Q11. A boat moving at constant speed v through still water experiences a total frictional drag F. What is the power developed by the boat? (A) 1 2 Fv (B) Fv (C) 1 2 Fv 2 (D) Fv 2 Q12. The work done by the force is defined as W = F.S. in the certain situation F and S are non- zero but the work done is zero from this we conclude that? (A) F and S are in the same direction (B) F and S are at right angle (C) F and S are opposite direction (D) None of above Q13. A body of mass m is dropped from a height h above the ground the velocity v of the body when it has lost half its initial potential energy is given by (A) gh (B) 2gh (C) gh /2 (D) none Q14. How much work must be done by a force on a 50 kg body in order to accelerate it from rest to 20 m/s in 10 sec. (A) 2x 10 3 j (B) 10 4 j (C) 10 3 j (D) 4x10 4 j Q15. A mass 2 kg is released from a height of 100 m. what will be kinetic energy when its height is from the ground is 60 m (A) 800 j (B) 400 j (C) 600 j (D) 1200 j
www.youtube.com/physicswithshahid WORK & ENERGY (UNIT-2) MDCAT Q16. Two particles of masses m and 4m have kinetic energies in the ratio of 2:1, what is the ratio of linear momentum? (A) 2 1 (B) 2 1 (C) 4 1 (D) 16 Q17. A crane can raise a body of mass 120kg vertically upward with a speed of 4.5 ms-1 . What is the power of its engine. (A) 5.3 kw (B) 6.3 kw (C) 7.3 kw (D) 8.3 kw Q18. A vertically projected body had its energy (A) Maximum at higher point (B) Same at all points (C) minimum at higher point (D) None of the above Q19. A person of mass 60 kg carries a 15 kg body on the top of building 10m high in 5 min. he puts a power in carrying the body (A) 10 W (B) 5 W (C) 30 W (D) 15 W Q20. A force of 5N acts on a body of weight 9.8 N. what is the acceleration produced in m/s2 (A) 0.51 (B) 1.46 (C) 49 (D) 5 Q21. Amount of work done is required to accelerate a 1000 kg of car from 20 m/s to 30 m/s is (A) 25 x 101 J (B) 2.5 x 103 J (C) 2.5 x 104 J (D) 2.5 x 105 J Q22. The retarding force required to reduce velocity of 3kg body from 0.75m s־1 to 0.25 ms ־1 in 0.02 seconds will be (A) 100N (B) 75N (C) 50N (D) 25N Q23. A stone of weight 4.0 N in the Earth’s gravitational field is moved from P to Q and then to R along the path shown. How much P.E. does the stone gain? (A) 120 J (B) 200 J (C) 280 J (D) 1200 J