# Homework Help: Poorly worded question

1. Nov 1, 2004

ok here is the question exaclty- its worth 5 marks so i dont know what im missing..

A car with a mass of 850kg is moving in a straight line at a constant speed of 110km/h. It is brought to rest in 10.0s. What constant force is acting to stop the car?

2. Nov 1, 2004

### mathlete

$$F_{avg}\Delta t = m\delta v$$

3. Nov 1, 2004

### Parth Dave

Looks like an impulse question.

4. Nov 1, 2004

Thanks anyways guys but i got it. I think i was thinking it was asking what force as in friction or wind etc. was stopping it but its asking the force it would take to stop it in that time.

5. Nov 1, 2004

### Staff: Mentor

If you are not familiar with impulse/momentum, you can always use kinematics to find the acceleration, then apply Newton's 2nd law to find the force.

6. Nov 2, 2004

### cepheid

Staff Emeritus
Good point...I guess they should have said "determine the magnitude of the constant force that brings the car to a stop".