- #1
zorro
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Product of my imagination (not a homework/textbook question)-
A body is kept on top of a hill of height 'h'. If we fix the 0 potential energy at the ground, the body has an initial energy - mgh. Assume that the hill surface + ground is frictionless. When the body starts sliding (with negligible push), it gains a velocity of v=(2gh)1/2 on reaching the ground, which follows from energy conservation.
Now suppose we observe the whole situation from a reference frame moving with a uniform velocity v=(2gh)1/2 on the ground. Initially, the body has a total energy given by 0.5mv2 + mgh. On reaching the bottom, the total energy is 0!
Where does the energy vanish?
A body is kept on top of a hill of height 'h'. If we fix the 0 potential energy at the ground, the body has an initial energy - mgh. Assume that the hill surface + ground is frictionless. When the body starts sliding (with negligible push), it gains a velocity of v=(2gh)1/2 on reaching the ground, which follows from energy conservation.
Now suppose we observe the whole situation from a reference frame moving with a uniform velocity v=(2gh)1/2 on the ground. Initially, the body has a total energy given by 0.5mv2 + mgh. On reaching the bottom, the total energy is 0!
Where does the energy vanish?