Answer to Question #168855 in Mechanics | Relativity for April

Question

The IMA of the pulley system shown in figure 3 is 4, how far must the applied force move if

the load moves 1 ft? If the load weighs 200 lb and the efficiency of the system is 90 %, what

must be the applied force?

Answer 1

The distance of applied force moving is:

$d_2=IMA\cdot d_1=4\cdot 1=4\space ft.$

The applied force is:

$F=\frac{mg} {0.9IMA} =\frac{90.7\cdot 9.8} {0.9\cdot 4} =246.9\space N.$

Answer: 4 ft, 246.9 N.