I am working on the following problem:

The braking acceleration for a car based on data in a driver’s handbook is –12.2 m/s2. If the car has a mass of 925 kg, find the frictional force and state the direction.

So far I have done the following: F = ma F = (925)(-12.2) F = -11285N

I believe that the net force (-11285) = the force of friction.

Is there any way to calculate the coefficient of friction in this problem with only the above information?


1 Answer 1


It is unclear exactly what your problem is from the information provided, so with this answer I am assuming that friction is the only force being applied to the car, and that the car is sliding to a halt, so we are looking for a coefficient of kinetic friction.

Under those assumptions, $F_{net} = f_k$. Therefore your frictional force is: $f_k = 11285N$. From this you can use the following equation: $$f_k = n*\mu_k$$ to find the coefficient, of kinetic friction, $\mu_k$.

Again, this is only if the car is sliding, and friction is the only force being applied.


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