# Homework Help: Momentum+Physics Question

1. Sep 10, 2008

### RajdeepSingh7

Momentum+Physics Question :D

Hey Everyone.
This is a question which I have received and have completed to the best of my ability.
I was wondering if anyone would be willing to look over it too see if I was correct, and maybe aide me with the last two questions

The Question is:

In a crash test program, cars are fitted with dummies ( named Matt, Hugo and Fred ) which have similar characteristics and masses to humans. The cars are then accelerated and crashed into concrete walls with high speed camera recording the effects o the occupants of the vehicle. One such vehicle, a "Fasty" has a mass of 1200 kg and is accelerated from rest to 13.5 ms^(-1). The car is then brought to rest in a head on collision with a wall. The collision time was 80.0 milliseconds.

(a)

What is the momentum of the car before it collides with the wall?

Using,
p=mv

And Values:
m= 1200
v= 13.5

p=(1200)(13.5)
Momentum = 16200 kg ms^(-1)

(b)

What is the impulse exerted on the car by the wall?

Using,
Impulse = Change In Momentum

Initial Momentum = 16200 kg ms^(-1)
Final Momentum = (1200)(0)= 0 ms^(-1)

Therefore, Impulse = 16200-0= 16200 Newton Seconds

(c)What is the average force exerted by the car on the wall?

Using,
Average Force = Impulse/Change In Time
=16200/0.080
Average Force = 202500 Newtons.

(d) The front of the "Fasty", crumples on impact. How would the impulse and the force have compared if the front of the "Fasty" had not crumpled?
&
(e) One of the dummies, Fred (body mass 60kg), was not strapped into a seat belt. As a result of the collision with the wal, Jamie was projected through the windscreen and collides head first ino the wall. Use the data below to determine the force exerted on Jamie's Skull.

Estimates: Mass of Jamie's Skull = 5 kg
Collision Time = 0.5 Seconds

The following questions I am having trouble starting off, so If anyone could start them off for me it would be appreciated.

Any Help and correction will be greatly appreciated, and I will post any progress I make on the problem.