Question

a) State the “Principle of Conservation of Energy”. (1+2)
b) Heat is a form of energy. State any two applications of heat energy.

Answer 1

Answer:

A.L. Stanford, J.M. Tanner, in Physics for Students of Science and Engineering, 1985

5.6 Problem-Solving Summary

Like many other physical concepts, work, power, and energy are most effectively used in solving problems by applying the definitions of these concepts strictly and carefully to the problem at hand.

The definition of work, Wa→b = ∫ba F·ds, suggests a number of practical facts that are useful in problem-solving. First, work is done by a force F applied to an object when that object moves from point a to point b. It follows that no work can be done on an object unless the object moves. Furthermore, no work is done by F unless there is a component of F along the direction of the displacement of the object. Only the component of a force parallel to the displacement of an object can do work on that object. The integral in the definition of work suggests that the work done by the force F as the object moves from a to b is equal to the area enclosed by the curve of Fs(s), the component of F parallel to ds; the s axis; and the lines s = a and s = b. Simpler situations, like the frequently encountered case of a constant force acting on an object that moves in a straight line, say the x axis, are special cases of the general definition of work. For this case, the work by a constant force, F = Fxî + Fyĵ, on an object moving along the x axis