Question

What minimum distance can a truck slide on a horizontal asphalt road if it is travelling at 30m/s? The coefficient of friction between the asphalt and the tire is at 0.4. The weight of the truck is 7500 kg.

Answer 1

$F_f=ma\to a=F_f/m=\mu mg/m=\mu g=0.4\cdot9.8=3.92\ (m/s^2)$

$v=v_0-at\to 0=v_0-at\to t=v_0/a=30/3.92=7.65\ (s)$ . Answer