A particle moves in a straight line with a constant velocity of 20 m/s for 10 seconds. It is then subjected to a constant acceleration of 5 m/s2 in the opposite direction for T seconds, at which time the particle is back to its original position. a) Sketch the velocity-time graph representing the motion. b) Find how long it takes the particle to return to its original position.

A particle moves in a straight line with a constant velocity of 20 m/s for 10 seconds. It is then subjected to a constant acceleration of 5 m/s2 in the opposite direction for T seconds, at which time the particle is back to its original position. a) Sketch the velocity-time graph representing the motion. b) Find how long it takes the particle to return to its original position.