Question

A 52 kg skateboarder is standing on the edge of a 35 m tall half-pipe.

How much energy will the skateboarder have when he drops in the pipe?

What will his kinetic energy be when he reaches the bottom?

Calculate his speed using the energy from the question above.

Answer 1

Answer:

The speed I got is 26.2m/s (3sf)

Explanation:

When the skateboarder is standing at the edge of the half-pipe, they would have max gravitational potential energy of about 17800J (3sf), calculated by using this formula;

Gravitational potential energy (Eₚ) = mgh

Eₚ = 52 × 9.8 × 35

Eₚ = 17836J

Eₚ = 17800J (3sf)

As the skateboarder drops, this energy will also decrease because they are losing height and gets converted into kinetic energy. Hence, the kinetic energy increases. When they reach the bottom (assuming they haven't landed and stop moving), the skateboarder will reach max kinetic energy.

To calculate the speed from this energy, we can use this formula;

Eₖ = 1/2 × m × v²

Substitute the values;

17800 = 1/2 × 52 × v²

17800 = 26 × v²

v² = 17800/26

v = √684.6

v = 26.2m/s (3sf)