A bob of mass of 0.18 kilograms is released from a height of 45 meters above the ground level. What is the value of the kinetic energy gained by the bob at the ground level?

Question

Shadow · Answer

$$PE = KE$$
$$m g h = \frac{ 1 }{ 2 } m v^2$$

Shadow · Answer

This is all you need since 45m -> ground level means that were was a complete conversion of all PE (potential energy) to KE (kinetic energy) as there is no more height (and without height there can't be any PE).

Shadow · Answer

Since m is on both sides, we can get rid of that, we are left with:
$$gh = \frac{ 1 }{ 2}v^2$$
Gravity is approx 9.8m/s^2, they give you height (45m). The only variable left is v^2 which is the unknown for KE. Solve for that and you have your answer. All you have to do is input your variables.

Shadow · Answer

Note: Different teachers use different approximations of gravity. Some use 10m/s^2 or 9.8m/s^2, so if your teacher used something different, then it is best to abide by that.

oscar1rivera · Answer

shadow thanks

Shadow · Answer

No problem. Do you know how to proceed?