Question

A cart of weight 10 N is pulled 1.2 m up a ramp by an applied force of magnitude 5.0 N [parallel to the ramp], raising the cart 0.50 m above its initial level. Calculate the percent efficiency of the work.

• A. 83.33%
• B. 85%
• C. 84.5%
• D. 86.33%

Answer 1

The correct option is A. 83.33%

Weight of the cart = mg = 10 N

Vertical height = h = 0.5 m

Force = F = 5 N

Displacement along the plane = 1.2 m

Energy output = Potential energy = m $\times$ g $\times$ h = 10 $\times$ 0.5 = 5 J

Energy input = Work done to move the cart = F $\times$ displacement = 5 $\times$ 1.2 = 6 J.

Percentage efficiency = $\frac{energyoutput}{energyinput}$ = $\frac{5}{6}$ $\times$ 100 = 83.33%.