Velocity-time graph for the motion of a certain body is shown in Fig. Explain the nature of this motion. Find the initial velocity and acceleration and write the equation for the variation of displacement with time. What happens to the moving body at point B? How does the body moves after this moment?

Explanation

The velocity - time graph is a straight line with-ve slope. The motion is uniformly retarding up to point B and there after uniformly accelerated up to C.
At point B the body stops and then its direction of velocity reversed.
The initial velocity at point A is `v_(0)=7ms^(-1)`.
`therefore a=(v_(f)-v_(o))/(Deltat)=(0-7ms^(-1))/(11s)=(-7)/(11)ms^(-2)`
`=0.64ms^(2)`
The equation of motion for this body which gives variation of displacement with time is
`S=7t-(1)/(2)0.64t^(2)=7t-0.32t^(2)`.