- #1

CaptainOfSmug

- 13

- 0

## Homework Statement

A 2000-kg truck is sitting at rest (in neutral) when it is rear-ended by a 1000-kg car going 28m/s .After the collision, the two vehicles stick together.

#1What is the final speed of the car-truck combination?

#2What is the kinetic energy of the two-vehicle system before the collision?

#3What is the kinetic energy of the system after the collision?

#4Based on the results of the previous parts, what can you conclude about which type of collision this is?

#5Calculate the coefficient of restitution for this collision.

## Homework Equations

## The Attempt at a Solution

Okay, so for the record I got all these answers correct (masteringphysics) if you've had to use this horrendous program :p

#1So for the final speed of the car-truck combination:

1000(28)+2000(0)=m

_{12}(V

_{12xf}

=9.33m/s

#2 The kinetic energy of the two vehicle system before the collision:

K

_{car}=0.5(mv

^{2})

.5(1000)(28)^2

=392000J

#3 KE after the collision:

K

_{truckandcar}=.5(1000+2000)(9.33)

^{2}

#4 what type of collision is it?

I know the answer is totally inelastic but I cannot figure out why? By my books definition the final velocity of the truck and car must equal 0? Am I wrong here or can someone explain this for me?

#5 Since the answer to the previous question was totally inelastic I can assume e=0, but when I calculate it out this is not the case. I need an explanation on this to help my understanding of this! Thanks in advance!