You are Here: Home >< Physics

# Need a little help with a Physics Question watch

1. Hey guys,

I don't know whether this is the right place to come but I need some help with a physics question, please take note that this isn't very high end stuff so you need not to worry lol. ( I know it's probably very easy but I'm in need of reassurance from people if I am to answer it.)

So the question is as follows:

A car moving at 20m/s has 160 000J of kinetic energy. Write down an equasion and then use it to calculate the average braking force acting on the car to bring it to rest over a distance of 25m.

Now I'm assuming that the equasion would be something to do with force but that's the reason I'm here, I'm not quite sure how to answer it.

So if somebody knows how to answer this question I would highly appriciate it if you could take me along steps of how about going to answer this question.

Thank you for reading and I hope that someone knows how to figure this one out!
2. Work done = force*distance

The work done in this case has to equal the kinetic energy of the car. In order for the car to be at rest, its kinetic energy must be equal to zero.
The distance 25m is given to you in the question.
The equation above can be rearranged to find the required force:

work done/distance = force.

Put the values into the above formula to find the average force needed to bring the car to rest in 25m. Remember the units of force are N (newtons).
3. Thank you very much

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: March 18, 2011
Today on TSR

### University open days

Wed, 25 Jul '18
2. University of Buckingham
Wed, 25 Jul '18
3. Bournemouth University
Wed, 1 Aug '18
Poll
Useful resources

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE