# What is the gravitational potential energy of a  2 kg object on a shelf  1/2 m  high?

$\text{9.8 Joule}$
Potential energy ($\text{U}$) is given by
$\text{U = mgh}$
$\text{U" = cancel(2)\ "kg × 9.8 m/s"^2 × 1/cancel(2)\ "m" = "9.8 Joule}$