Question

A crowbar of length 2.0 m is used as a machine to lift a box of 100 kg f by placing a fulcrum at a distance of 0.1 m from the box. Calculate the effort required.

Answer 1

1. Definition:

Mechanical advantage:

The ratio of force produced by a machine to the force applied to it.

Mechanical advantage = $\frac{load}{effort}$

Velocity ratio:

The ratio of distance traveled by the load to the distance traveled by effort.

Velocity ratio = $\frac{loadarm}{effortarm}$

2. Solution:

Given that,

Length of crowbar = 2m

length of load = 2-0.1 = 1.9m

length of effort =0.1

Velocity ratio = $\frac{loadarm}{effortarm}$= $\frac{1.9}{0.1}$ = 19

Mechanical advantage (M.A)= velocity ratio(V.R) x efficiency

If the efficiency is negotiable (100 %) then,

M.A= V.R

19=$\frac{100}{Effort}$

Effort = 5.62kgf

3. Conclusion:

hence, the effort required is 5.62kgf.