Question

Suppose a child drives a bumper car head on into the side rail, which exerts a force of 3900 N on the car for 0.55 s. Use the initial direction of the cars motion as the positive direction.

What impulse, in kilogram meters per second, is imparted to the car by this force?
Find the horizontal components of the final velocity of the bumper car, in meters per second, if its initial velocity was 2.95 m/s and the car plus driver have a mass of 190 kg. You may neglect friction between the car and floor.
Find the horizontal components of the final velocity of the bumper car, in meters per second, if its initial velocity was 2.95 m/s and the car plus driver have a mass of 190 kg. You may neglect friction between the car and floor.

Answer 1

The impulse is 2145 kg-m/s

The final velocity is -8.34 m/s or 8.34 m/s in he opposite direction.

Step-by-step 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 = 2145 kg-m/s

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 = -8.34 m/s