Question

Elect the correct equations that show that when a 3.0-kg book is lifted 2.6 m its increase in gravitational potential energy is 78 j .

Answer 1

The increase in gravitational potential energy for an object of mass m is given by
$\Delta U = mg \Delta h$
where $\Delta h$ is the increase in altitude of the object.

In our problem, m=3.0 kg, $\Delta h= 2.6 m$ and $g=10 m/s^2$ (approximated value), so we have
$\Delta U = mg\Delta h=(3.0 kg)(10 m/s^2)(2.6 m)=78 J$