Skateboarding Physics: Reaching New Heights

Which height will Fred reach after the collision?

After the collision, which height will Fred reach?

Answer:

The answer is h/4

Final answer:

In a semi-circular halfpipe scenario, Peter starting from rest at a height h and colliding with Fred will result in an inelastic collision, where they would not reach the initial height h due to the combined mass and shared kinetic energy post-collision.

Explanation:

The question you are asking regards a physical scenario involving conservation of energy and momentum in a skateboarding situation. When Peter, starting from rest at a height h, collides with Fred, who is at the bottom, the collision will exchange energy and momentum between the two. Assuming they have the same mass and the collision is perfectly inelastic (they stick together), they will move together with a combined mass of 2m (where m is the individual mass of Peter or Fred) and reach a new height that is less than h.

Based on the conservation of energy, because there are no external forces doing work (ignoring friction and air resistance), the potential energy at the initial height h will be equal to the kinetic energy at the bottom of the halfpipe. In an inelastic collision where the two objects stick together, they move with a common velocity after the collision. Since the kinetic energy after the collision must be shared by both masses, the combined system must have less kinetic energy per unit mass than Peter did alone before the collision, therefore, they won't reach the original height h.

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