The coefficients of friction between the load and the flatbe

The coefficients of friction between the load and the flatbed trailer shown are mu_s = 0.40 and mu_k = 0.35. Knowing that the speed of the rig is 55 miles/h, determine the shortest time in which the rig can be brought to a stop if the load is not to shift.

Solution

55 mi/h = 25 m/s

Consider the load A F_f = -mu_s (m_A g)

Using Principle of Impulse and Linear Momentum

F_f * delta t = m_A v₂ - m_A v₁

delta t = 25 / 0.4 * 9.8

= 6.38 s