Answer:
<em>The impulse is 2145 kg-m/s</em>
<em>The final velocity is -8.34 m/s or 8.34 m/s in he opposite direction.</em>
Explanation:
Force on the rail = 3900 N
Elapsed time of impact = 0.55 s
Impulse is the product of force and the time elapsed on impact
I = Ft
I is the impulse
F is force
t is time
For this case,
Impulse = 3900 x 0.55 = <em>2145 kg-m/s</em>
If the initial velocity was 2.95 m/s
and mass of car plus driver is 190 kg
neglecting friction, the initial momentum of the car is given as
P = mv1
where P is the momentum
m is the mass of the car and driver
v1 is the initial velocity of the car
initial momentum of the car P = 2.95 x 190 = 560.5 kg-m/s
We know that impulse is equal to the change of momentum, and
change of momentum is initial momentum minus final momentum.
The final momentum = mv2
where v2 is the final momentum of the car.
The problem translates into the equation below
I = mv1 - mv2
imputing values, we have
2145 = 560.5 - 190v2
solving, we have
2145 - 560.5 = -190v2
1584.5 = -190v2
v2 = -1584.5/190 = <em>-8.34 m/s</em>
