Objective: The motion of a body falling freely under gravitational attraction will be examined, and from themeasured rate at which the velocity changes with time the acceleration due to gravity (g) will bedetermined.IntroductionIf a body is acted upon by a net force, then that force causes the body to accelerate. If the force is constant in magnitude, then the acceleration of the body will also be constant. A body which is allowed to fall freely is acted upon by the force of gravitational attraction between that body and the earth, and is directed toward the center of the Earth. If the distance of the fall is very much less than the earth’s radius then this gravitational force is essentially constant in magnitude and the acceleration due to gravity (g) will be constant during the time of fall. We ignore here a second force of air resistance, which also acts on a falling body. However, for

smooth, dense bodies falling only a short distance, air resistance is very small. Its effect can be ignored in the present experiment. In Fig. 1 are shown curves representing the relationship between a) displacement and time, b) velocity and time, for a body moving at a constant acceleration. The acceleration is defined as the rat of change of velocity with time.a=v−v0tor V=V0+at….......……1)Where “a” represents the acceleration of the body whose velocity changes from an initial valueVoto a final velocity V in the time interval T. From equation 1) we see that a plot of v-vs-t should be a straight line if the acceleration is constant, as seen in Fig 1(b). The slop of this line is equal to the acceleration a. The average velocity of a body is defined as the total displacement (s), i.e.V=st…………………………………………2)For uniformly accelerated motion the average velocity is simply the arithmetic mean of the initialand final velocities (Vo& V) over the time interval, t, i.e.