A model engine accelerates forward from rest along a straight track at 10.0 m/s 2 for 3.0 seconds. It then accelerates forward at 16 m/s 2 for 5.0 seconds, and finally decelerates at 12m/s 2 until it stops. (a) Calculate how many seconds the engine was moving.

(b) What was its maximum velocity?

(c) Plot a velocity/time graph of its motion

(d) Find the total distance traveled.

While goofing off at the ice skating rink, a student takes off her shoes and places each of them on the ice. her friend, a hockey player, then shoots a hockey puck at each shoe. the first puck immediately comes to rest after it collides with the left shoe. the second puck rebounds after it collides with the right shoe. if each hockey puck has the same incoming speed, which shoe has greater speed after the collision? the right shoe. both shoes have the same speed. the left shoe.

A( developed during the process of technology design

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".