Question

please see attachment the question belongs to circular motion

Answer 1

mass of car, m = 1000kg
velocity, v = 5 m/s
radius, r = 25 m

The friction provides necessary centripetal force. So friction is equal to the centripetal force.

$f = \frac{mv^2}{r} = \frac{1000 \times 5^2}{25}=1000N$

Minimum friction required is 1000N.

Answer 2

f=mv*v/r
f=1000*5*5/25
f=1000
force is 1000newtons