Question

On a roller coaster the first hill has a height of 30m while the second hill has a height of 15m . If the coaster has a speed of 2m/s at the top of the first hill, what is its speed at the top of the second hill if 2% of the energy is lost to friction

Answer 1

total energy E = K + P ; K is kinetic energy ; P is potential energy

K = 1/2 * m * v^2
P = m * g * h

So for the first hill, figure out the total energy.

Then decrease that total energy by 2%.

Then calculate the energy at the second hill.

You can get speed from that.