a. It occures in binary systems where one of them is a whitedwarf
Answer:
The potential energy of the more massive one is twice that of the other.
Explanation:
Potential energy is given by
<em>PE</em> = <em>mgh</em>
where <em>m</em> = mass of body, <em>g</em> = acceleration of gravity and <em>h</em> = height or elevation.
For the less massive car, let the mass be
. Then its <em>PE</em> is

For the massive car, let the mass be
. Its <em>PE</em> is

But 

Hence, the potential energy of the more massive one is twice that of the other.
Average speed is worked out from dividing distance by time.
Answer: i think the answer is 20.0s
Explanation: