Question

You are standing on a bridge that's 50 feet above a river.You drop a quarter, and it starts to fall towards the river.When does the quarter have the most energy? (Assumethere is no air resistance.)

Answer 1

We are given that a quarter is dropped from a height of 50 ft. Since there is no air resistance this means that the total amount of energy is constant due to the principle of conservation of energy. We can calculate the amount of energy by having into account that at the beginning the type of energy the quarter has is potential energy, and it can be calculated using the following formula:

`E=\text{mgh}`

Where:

`\begin{gathered} m=\text{ mass} \\ g=\text{ acceleration of gravity} \\ h=\text{ height} \end{gathered}`

The mass of a quarter is approximately 0.0057 kg. Substituting in the formula we get:

We have converted the 50 feet into meters.

Solving the operations we get:

`E=0.85J`

Therefore, the amount of energy of the quarter will remain as 0.85 Joules.