# Homework Help: Newton's laws question -- a car coasts to a stop on a level road

1. Nov 23, 2014

### rmalski

1. The problem statement, all variables and given/known data
A 1490 kg car is is traveling at a speed of 22.2 m/s when the driver lets the car coast on a level road. The friction on the car slowing it down is 288 N. How far will the car coast?

2. Relevant equations f=ma

3. The attempt at a solution
i can find the force but i cannot find the distance, i found that the force is 32790N but i am stuck after that

2. Nov 23, 2014

### Staff: Mentor

Welcome to the PF.

Please show in detail your calculations so far. How did you get that number? You are given a force F and a mass m, use the equation you wrote to calculate the acceleration (deceleration in this case). How can you use the deceleration to figure out the time until the car stops?

3. Nov 23, 2014

### rmalski

well first i found the force by multiplying m and a, then i subtracted the friction force which is 288n. i got the force as 32790 and this is where i got stuck. i thought the acceleration is 22.2m/s^2?

4. Nov 23, 2014

### Staff: Mentor

You are given Force and mass, not acceleration a. You are given the initial velocity of 22.2m/s, which you will use after you calculate the acceleration to figure out how long it takes to stop.

5. Nov 23, 2014

### rmalski

ok thats where i messed up, so the acceleration is 288/1490 which is .193m/s^2?

6. Nov 23, 2014

### rmalski

ok i found it thank you

7. Nov 23, 2014

### Staff: Mentor

Great! :-)

Now post your other thread, unless you've figured it all the way out too... :-)