Question

A 2.5 x 10^3 kilogram truck with rubber tires moves

through a 120 meter radius turn on a dry asphalt

surface.

Calculate the maximum speed with which the

truck could have made this turn. (Ff=2.1 x 10^4)

Answer 1

The question implies that force of friction is 2.1E4 N

F = M v^2 / R frictional force needed to supply this centripetal force

2.1E4 = M v^2 / R

v^2 = R * 2.1E4 / M

v^2 = 120 * 2.1E4 / 2.5E3 = 1200 * 2.1 / 2.5 = 1008 m^2/s^2

v = 31.7 m/s max speed of truck (about 70 MPH)