m = mass of the car = 1800 kg
g = acceleration due to gravity = 9.8 m/s²
= force of gravity on the car
force of gravity on the car is given as
= mg
inserting the values
= (1800) (9.8) = 17640 N
= static frictional force acting on the car
from the force diagram of the car , the static frictional force is opposite to the parallel component of force of gravity on the car . hence static frictional force mus balance the component of force of gravity parallel to incline surface.
hence
=
Sin7
= (17640) Sin7
= 2149.8 N