Question

A 15 kg brick is laid at the top of a 30 m building. How much PE does it have? Round to the nearest whole

Answer 1

P.E. in this case is gravitational potential energy, for a mass m at a height h, gravitational P.E. is given by,

$P.E.=mgh$

where g is acceleration due to gravity, (g = 10 m/s^2)

Given,

$\begin{gathered} m=15\text{ kg} \\ h=30\text{ m} \end{gathered}$

So,

$\begin{gathered} P.E.=(15)(10)(30)\text{ J} \\ \Rightarrow P.E.=4500\text{ J} \end{gathered}$

Result: P.E. of the brick is 4500 J