Read each statement below. For each situation, calculate vi, vf, pi, pf, the impulse vector F􏰁t, and the amount of force needed for the change to occur. All situations refer to a truck with a mass of 2840 kg.

Question

1. The truck has a velocity of 8.30 m/s and comes to a stop in 15.0 s.
2. The truck, initially at rest, reaches a velocity of 8.30 m/s in 20.0 s.
3. The truck is at rest. In 5.00 s, the truck backs up to a speed of 1.38 m/s.
4. The truck is moving backward with a velocity of 1.38 m/s and comes to a stop in 5.00 s.

Answer 1

I'll do one of these. I don't see wht you can't do the others yourself. Give is a try.

1. The truck has a velocity of 8.30 m/s and comes to a stop in 15.0 s.
vi (inital) = 8.30 m/s
vf (final) = 0
pi (inital momentum) = 2840*8.3 = 23,572 kg*m/s
pf = 0
Impulse = pf - pi = -23672 kg*m/s
Force required = (impluse/time) =
-23672/15 = -1571 newtons
It is negative becasue the force must oppose the motion.

Answer 2

-1571 n