# Impulse exerted on car during collision

• naianator
In summary, two cars, one with mass 900kg and heading north at 25m/s, and the other with mass 700kg and heading west at an unknown speed, collide at a perpendicular intersection and stick together, moving in a direction 40∘ west of north and sliding 35m after the collision. The magnitude of the impulse exerted on car 1 during the collision is 10619.9 kg m/s and the magnitude of the impulse exerted on car 2 is also 10619.9 kg m/s. The momentum of car 1 before the collision is 22500 kg m/s and after the collision is 16521.6 kg m/s in the north-west direction. It is
naianator

## Homework Statement

Two cars are approaching a perpendicular intersection without a stop sign. Car 1 has a mass m1=900kg and is heading north at v1=25m/s. Car 2 has mass m2=700kg and is heading west at an unknown speed v2. The two cars collide at the intersection, and stick together as a result of the collision. The police report stated that after the collision, the two cars moved together in a direction 40∘ west of north and stopped after sliding d=35m from the collision point.

What is the magnitude of the impulse exerted on car 1 during the collision?

What is the magnitude of the impulse exerted on car 2 during the collision?

## Homework Equations

x(t) = x_o+v_o*t+1/2*a*t^2
mv = m1v_1'+m2v_2'
J = mv_f - mv_o

## The Attempt at a Solution

Velocity of car 2:
26.9711 m/s

Velocity after collision:
18.35729 m/s

Momentum of car 1 before collision: 22500 kg m/s

Momentum after collision: 1600 kg * 18.35729 = 29371.664 kg m/s

sqrt((29371.664)^2 - (22500)^2) = 18879.7
(which is equal to the momentum of car 2)

If I can figure out the first one I can do the second one I just need to know what I'm doing wrong.

In PF you want to show what you did to get these numbers...
I can follow this one, but generally it's impossible to find what goes wrong where ...

Momentum of car 1 before collision: 22500 kg m/s

Momentum after collision: 1600 kg * 18.35729 = 29371.664 kg m/s
Yes, but what is the momentum of car 1 after the collision ?
And then you want to make a drawing to see what the change of momentum for car 1 is.

BvU said:
In PF you want to show what you did to get these numbers...
I can follow this one, but generally it's impossible to find what goes wrong where ...

Yes, but what is the momentum of car 1 after the collision ?
And then you want to make a drawing to see what the change of momentum for car 1 is.
Would that be 18.35729*900 = 16521.6? Because 16521.6^2-22500^2 is a negative. Should I just use 16521.6sin40 = 10619.9?

naianator said:
Would that be 18.35729*900 = 16521.6? Because 16521.6^2-22500^2 is a negative. Should I just use 16521.6sin40 = 10619.9?
thats velocity after collision*mass of car 1*sin(theta)

What does the drawing tell you ? Do you realize that momentum is a vector ? It has two components !

naianator

## What is impulse?

Impulse is a measure of the change in momentum of an object. It is the product of the force exerted on an object and the time interval over which the force acts.

## How is impulse related to collisions?

In a collision, the impulse exerted on an object is equal to the change in momentum of the object. This means that the greater the impulse, the greater the change in velocity of the object.

## What factors affect the impulse exerted on a car during a collision?

The impulse exerted on a car during a collision is affected by the mass and velocity of the car, as well as the duration of the collision and the force exerted on the car.

## Can impulse be negative?

Yes, impulse can be negative if the force exerted on an object is in the opposite direction of its motion. This can occur in a collision if the car experiences a force that slows it down.

## Why is understanding impulse important in car collisions?

Understanding impulse in car collisions is important because it can help us design safer cars and improve safety measures. By understanding how impulse affects the change in velocity of a car during a collision, we can work towards reducing the force exerted on passengers and decreasing the risk of injury.

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