A car is travelling at 10m/s when it brakes and decelerates at 2ms^-2 to a stop. How long does the car take to stop?

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This is a question testing the knowledge of the equations of constant acceleration (Suvat equations)

First convert the question into a standard form. For example by writing out the variables as follows 

s (displacement) = unknown

u (initial velocity) = 10m/s

v (final velocity) = 0m/s

a (acceleration) = 2ms^-2

t (time) = unknown

You know v, u and a and you want to calculate t, therefore the equation you need to use is v = u + a*t

Re-arranging t = (v - u) / a 

Finally substituting in v, u and a, t = (10 - 0) / 2 = 5s

So the time taken for the car to stop is 5 seconds. 

Kirill M. A Level Maths tutor, A Level Further Mathematics  tutor, A ...

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