ABSTRACT
In section D1 several forms of mechanical energy were identified, principally gravitational potential energy, strain potential energy, linear and angular kinetic energy. The examples used the idea that chemical energy is used by the muscles to generate muscle tension. The muscle is essentially a device which converts chemical to mechanical energy. When energy changes from chemical to mechanical a certain amount of heat is given off. The heat is a by-product of the energy conversion process and while it may have some biological value in maintaining body temperature it does not generally contribute to the performance and so is considered a waste product. Energy conversion processes often produce heat as a by-product. For example, when a ball is dropped it is compressed as it hits the ground and after the recoil never quite reaches the same height from which it was dropped. This failure to regain the original drop height is due to a loss of energy as a result of the compression and is indicative of the efficiency of energy conversion which, if heat is generated, is always less than 100%. If that compression
to good effect in the game of squash where the warm ball rebounds with greater speed than a cold ball.
