Question

In raising a 3000-N piano with an IDEAL pulley system, it is noted that for every 2 m of rope pulleddown, the piano rises 0.2 m. What force is needed to lift the piano?

Answer 1

We have

Fo=3000N

do=0.2m

di=2m

We know that the formula

$W=F\cdot d$$W_{\text{output}}=W_{in\text{put}}$$F_0d_0=F_id_i_{}$

The force is equivalent to the weight

$F_i=\frac{F_0d_0}{d_i}$$F_i=\frac{3000\cdot0.2}{2}=\frac{600}{2}=300$

The force required to lift the piano is 300N