Question

A block of mass 44 kg is resting on a horizontal surface and there is a coefficient of friction of 0.63 between the block and the surface. The 44 kg block is attached by a string over a pulley to a hanging block of mass 32 kg. The blocks are released from rest, how long will it take the 32 kg mass to reach the ground 6.4 m below?

Answer 1

$$(m_1+m_2)a=m_2g-\mu m_1 g=(m_2-\mu m_1) g\\(44+32)a=(32-0.63(44)) 9.8\\a=0.55\frac{m}{s^2}\\h=0.5at^2\\6.4=0.5(0.55)t^2\\t=4.8\ s$$