# Question #56a40

Feb 9, 2017

At the top of the first hill of its track

#### Explanation:

We know that Gravitational Potential Energy of an object is given by the equation

$P {E}_{G} = m g h$
where $m$ is the mass of object, $g = 9.81 {\text{ ms}}^{-} 2$ is acceleration due to gravity and $h$ is height of object.

From the equation we see that $g \mathmr{and} m$ are constants for the roller coaster car. Clearly, maximum gravitational potential energy will be at the highest point. This is top of first hill.

This can also be seen from the figure. Also note that other hill is of lesser height.

$P {E}_{G} = 650 \times 9.81 \times 24 = 153036 \text{ J}$