Question

A man of mass 80.0 kg stands on a platform of mass 40.0 kg. He pulls on a rope that is fastened to the platform and runs over a pulley on the ceiling. With what force does he have to pull in order to give himself and the platform and upward acceleration of 1.0 m/s²?

Answer 1

Answer:F=648 N

Explanation:

Given

mass of man $m_1=80 kg$

mass of Platform $m_2=40 kg$

acceleration of system $a=1 m/s^2$

Let F be the force with which man pulls the rope which will also create a tension of F in rope

From Diagram

$2F-(m_1+m_2)g=(m_1+m_2)a$

$2F=(m_1+m_2)(g+a)$

$F=\frac{(m_1+m_2)(g+a)}{2}$

$F=\frac{(80+40)(9.8+1)}{2}$

$F=\frac{1296}{2}$

$F=648 N$