12.The position of an object moving along a straight line is represented by 3(t) = 21:3 - 15t2 + 36t + 10, where t is in seconds and sin metres. a) What is the velocity and the acceleration of the object at t=1. b) When is the object momentarily at rest? What is the object's position when stopped? c) When is the object moving in the positive direction? Negative direction? d) When is the object speeding up/ slowing down? e) What is the total distance travelled during the first 7 seconds? f) Sketch a diagram to illustrate the motion