A 4500 kg car accelerates from rest to 45.0 km/h over a distance of 90 m. Find the net force
acting on the car.

please help

The car undergoes an acceleration a such that

(45.0 km/h)² - 0² = 2 a (90 m)

90 m = 0.09 km, so

(45.0 km/h)² - 0² = 2 a (0.09 km)

Solve for a :

a = (45.0 km/h)² / (2 (0.09 km)) = 11,250 km/h²

Ignoring friction, the net force acting on the car points in the direction of its movement (it's also pulled down by gravity, but the ground pushes back up). Newton's second law then says that the net force F is equal to the mass m times the acceleration a, so that

F = (4500 kg) (11,250 km/h²)

Recall that Newtons (N) are measured as

1 N = 1 kg • m/s²

so we should convert everything accordingly:

11,250 km/h² = (11,250 km/h²) (1000 m/km) (1/3600 h/s)² ≈ 0.868 m/s²

Then the force is

F = (4500 kg) (0.868 m/s²) = 3906.25 N ≈ 3900 N

they should be similar or the same

the displacement produced by the body.  

the amount of force subjected to the body.  

the angle between the direction of force and displacement