# Help with Forces

I need help with this question:

A 1600.3 kg car is traveling at 26.4 m/s when the driver takes his foot off the gasd pedal. It takes 4.5 s for the car to slow down to 20 m/s. How large is the net force slowing the car? Answer in units of N.

I suck with forces and I have no idea how to do this. Can someone please help me out?

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ant124m said:
I need help with this question:

A 1600.3 kg car is traveling at 26.4 m/s when the driver takes his foot off the gasd pedal. It takes 4.5 s for the car to slow down to 20 m/s. How large is the net force slowing the car? Answer in units of N.

I suck with forces and I have no idea how to do this. Can someone please help me out?
To get a force you need an acceleration. How might you find an acceleration for the problem?

-Dan

topsquark said:
To get a force you need an acceleration. How might you find an acceleration for the problem?

-Dan
Would I have to use the formula v = v0 + at?

ant124m said:
Would I have to use the formula v = v0 + at?
Sounds good to me! -Dan

But what would v equal since I am given two velocities?

basic defintions

u stated the right formula...
just go to the basics..
what is acceleration?? it is the rate of change of velocity.
The two velocities given to you are for two different instances of time.
Hope that helps.

Can someone please provide a little more help for this problem, I have a very similar problem and I am stumped. Can you use a= Vo-Vf/t and then use the formula F=ma to get the force???

Of course. But it looks more like $$a = \frac{v_{f}-v_{0}}{t}$$. 