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# Friction/acceleration question

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1. The driver of a car travelling in a straight line, level road suddenly brakes.
The car slides 10m in 2 seconds before stopping. Assuming constant deceleration, find the co-efficient of friction between the tyres and the road.

I got given this question as homework after doing a lecture on turning moments so that put me on the wrong foot straight away.

So ive assumed I need to find the velocity first using d/t the find the acceleration using s=u.t + 0.5.a.t2

but then im lost. Can anyone point where im going wrong?
2. You need to use

The normal reaction , and the frictional force

So you just need to calculate the acceleration of the car, and then you can find
3. so do I need the mass value to complete this?
4. No, the mass cancels out
5. would you also use this method for this question

or would this be better solved using the energy method?

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