Question

The potential energy of an apple is 4.5 joules. The apple is 3.2 meters high. What is the mass of the apple?

Answer 1

The mass of the apple is `143.5 g`

Explanation:

Potential energy in joules is mass (in kg,) multiplied by the acceleration due to gravity (9.8 m/sec^2) multiplied by height in meters.

`E_p=mgh`

Rearranging to make the mass the subject:

`m=E_p/(gh) = 4.5/(9.8*3.2) = 0.143` `kg` or `143` `g`

Hence it is 4.5 divided by (9.8 times 3.2) multiplied by 1000 for converting into grams, i.e. approximately `143.5 g`.