Chapter 11, Problem 76A

To determine

The forms of energy are involved in catapulting a rock into the castle wall.

Explanation of Solution

Introduction:

A catapult is a device that used to project an object at a great distance without the aid of any propellent. The stored energy in the catapult is elastic potential energy which is produced by turning the catapult arm by using a tightly wound rope. Therefore, the sudden release of catapult arm gives the sudden energy, used to propel the payload of catapult which help to assault castles.

In the wound rope of the catapult, the energy stored is elastic potential energy which is produced by turning the catapult arm. This energy does work on the rockto throw it into the air. The rock during the flight through the air, experiences a mechanical energy which is the sum of potential energy and kinetics energy.

When rock hits the wall, the collision between the wall and rock is inelastic which convert most of the mechanical energy into sound energy and thermal energy which play a role to break apart the wall structure.

Conclusion:

The form of energy involved in catapulting a rock to the castle wall is elastic potential energy, kinetics energy and the potential energy.