This question has two parts to it. I will type the questions for both parts, along with additional info in "Description".

Question

A car with a mass m = 1190 kg is moving at a speed s = 22.2 km/h and needs to stop in a distance d = 41.3 m.

Part a) Write an expression for the magnitude of the net force on the car as it is stopping in terms of the symbols given in this problem description.

Part b) What is the magnitude of the net force on the car as it is stopping, in N?

Answer 1

a)

v² – v₀² = –v₀² = 2ax from kinematics. v = 0 when the car stops.

Solving for a gives

a = –v₀²/(2x)

The net force is given by

F = ma = –mv₀²/(2x)

b)

Plugging in m = 1190 kg, x = 41.3 m, and v₀ = 22.2 km/h × 1000 m/km × (1/3600) h/s = 6⅙ m/s

F = –(1190)(6⅙)²/(2(41.3)) ≈ –548 N