Question

A wheel barrow is used to lift a 150 lb load. The length from the wheel axle to the center of the load is 2 ft. The length from the wheel and axle to the effort is 6 ft. a. What is the ideal mechanical advantage of the system? b. Using static equilibrium calculations, calculate the effort force needed to overcome the resistance force in the system.

Answer 1

Answer:

$3:1$

$50\ \text{lb}$

Explanation:

$F_r=150\ \text{lb}$

Mechanical advantage is will be the ratio of the distances from the wheel axle of the forces.

$MA=\dfrac{6}{2}\\\Rightarrow MA=3:1$

The ideal mechanical advantage of the system is $3:1$.

The moment in the system is conserved so moment about the wheel axle is

$M_e=M_r\\\Rightarrow 6F_e=2F_r\\\Rightarrow F_e=\dfrac{2F_r}{6}\\\Rightarrow F_e=\dfrac{2\times 150}{6}\\\Rightarrow F_e=50\ \text{lb}$

The required effort force is $50\ \text{lb}$.