Position time graph of a particle moving along straight line is shown which is in the form of semicircle starting from t=2 to t=8 s. Select correct statement:-


a) Velocity of particle between t=0 to t=2 s is positive
b) Velocity of particle is opposite to acceleration between t=2 to t=5 s
c) Velocity of particle is opposite to acceleration between t=5 to t=8 s
d) Acceleration of particle is positive between t₁=2 s to t₂=5 s while it is negative between t₁=5 s to t₂=8 s

From the figure we can see that the velocity is zero from t=0 to t=2 second because position does not changes. Then position increases up to 5 second, so velocity is positive here, then position decreases up to 8 second hence the velocity is negative here, then velocity becomes zero and does not changes. From 2 to 5 second we can see that the increment of position decreases, so acceleration is in the opposite direction to the velocity. and from 5 to 8 second the magnitude of velocity increases, so direction of acceleration and velocity are same. So the statement (b) is correct.