Question

A 513 kg car is moving on a level road at 47.1 m/s. How large a retarding force (assumed constant) is required to stop it at a distance of 67.1 m?

Answer 1

Given,

Mass (m) = 513 kg

Initial Velocity (u) = 47.1 m/s

Distance (S) = 67.1 m

Final Velocity (v) = 0 m/s

v² = u²-2aS

(0)² = (47.1)² - (2*a*67.1)

0 = 2218.41 - 134.2a

134.2a = 2218.41

a = 16.53 m/s²

Retarding Force = ma

= 513*16.53 N

= 8479.89 N

The Retarding force is 8479.89 N.

I hope this helps.