Answer
The magnitude of the friction force on the car is 6750 N
Work Step by Step
The centripetal force is the net force which keeps an object moving in a circle. In this case, the force of friction provides the centripetal force.
$F_f = \frac{mv^2}{r}$
$F_f = \frac{(1500~kg)(15~m/s)^2}{50~m}$
$F_f = 6750~N$
The magnitude of the friction force on the car is 6750 N.