The gravity of the Sun causes the planets to move in a circular path. This is because of Newton's first law of motion.
According to Newton's first law, the body will remain at rest or in uniform motion untill external unbalanced force acts.
There are two forces acting on planets i.e. gravitational force and inertia of their orbits. <em>So, form Newton's first law the planets keeps on moving in a circular path.</em>
The law of effect given by Edward Thorndike explains the behavior of child given in the problem . The effect which gives pleasure and satisfying effect are likely to be learnt easily and the effect which creates bad taste are likely to be forgotten easily . actions producing feel good effect are likely to be repeated in future .
