Question

A 10kg ball raised up by 2 m possesses energy called potential energy given by u=mgy, where g=9.8 m/s^2. What is the value and units of potential energy, u, for this ball?

Answer 1

Using what we are given, we know what each variables represent. 'U' represents gravitational potential energy whose units are derived from the variables on the other side of the equation. 'm' represents mass, 'g' is the acceleration due to gravity, and 'y' is the height above the reference point. We can associate the 10 kg with mass because this is the quantity measured by mass and 2 m represents 'y' as this is the height above the reference point. Using the mentioned equation and multiplying we obtain the following:\[u = (10 kg) * (9.8 m/s^2) * (2 m) = 196.2 kg m/s^2\]
This would be the numeric answer for gravitational potential energy expressed in terms of base units. The derived unit for gravitational potential energy is the Joule (J). Thus, our answer could also be expressed as 196.2 J.