Question

a cyclist and bicycle have a combined mass of 90 kg. starting from rest, the cyclist rides down a 10 m high hill and up a 7 m high hill without pedaling the bicycle. what is the potential energy of the cyclist and bicycle at the top of the 7 m hill with respect to the bottom of the 7 m hill? a 900 j b 2700 j c 6300 j d 9000 j

Explanation:

Step1: Recall potential - energy formula

The formula for gravitational potential energy is $U = mgh$, where $m$ is the mass, $g$ is the acceleration due to gravity ($g= 10\ m/s^{2}$), and $h$ is the height.

Step2: Identify values

We are given that $m = 90\ kg$, $g = 10\ m/s^{2}$, and $h = 7\ m$.

Step3: Calculate potential energy

$U=mgh=90\times10\times7 = 6300\ J$

Answer:

C. 6300 J