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A rock of mass m is dropped to the groun...

A rock of mass `m` is dropped to the ground from a height `h`. A second rock, with mass `2m`, is dropped from the same height. When the second rock strikes the ground, what is its kinetic energy? (a) Twice that of the first rock, (b) four times that of the first rock, (c) same as that of the first rock, (d) half as much as that of the first rock, (e) impossible to determine.

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a. The more massive rock has twice as much gravitational potential energy associated with it compared with that of the lighter rock. Because mechanical energy of an isolated system is conserved, the more massive rock will arrive at the ground with twice as much kinetic energy as the lighter rock.
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CENGAGE PHYSICS-WORK, POWER & ENERGY-Exercise 8.3
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  2. A small block of mass 100 g is pressed again a horizontal spring fixed...

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  3. A rock of mass m is dropped to the ground from a height h. A second ro...

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  4. Three identical balls are thrown from the top of a building, all with ...

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  5. A lorry and a car moving with the same kinetic energy are brought to r...

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  6. In case of a moving body as force of friction is mumg, can we regard m...

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  7. A particle of mass m=5.00kg is released from point A and it slides on ...

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  8. Two objects are connected by a light string passing over a light, fric...

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  9. At time t, the kinetic energy of a particle is 30.0J and the potentia...

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  10. Under the action of a force, a 2 kg body moves such that its position ...

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  11. A uniform rod of mass M and length L is held vertically upright on a h...

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  12. A uniform chain of length l and mass m overhangs a smooth table with i...

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  13. Figure, a block slides along a track from one level to a higher level ...

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  14. Two smooth balls of mass m1 and m2 connected by a light inextensible s...

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  15. In figure, an inextensible string that connects two bodies of mass M a...

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  16. A block slides down a curved frictionless track and then up an incline...

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  17. A child's pogo stick(figure) stores energy in a spring with a force co...

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  18. A block of mass m is released from point (A) in figure. The track is f...

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  19. In figure, the stiffness of the spring is k and mass of the block is m...

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