Bill used a first-class lever to lift a heavy boulder that had a mass of 20 kg. He pushed down on one end of the lever with 40 N force. This end of the lever went down 0.6 m. This resulted in the boulder lifting 0.1 m. Calculate the efficiency of the lever.
To calculate the efficiency of the lever, we first need to find the work done by both the effort force (Bill's force) and the resistance force (the boulder's weight). Then we can use the formula for efficiency:
Efficiency = (useful work output / total work input) * 100%
Let's break it down step by step:
1. Find the work done by the effort force (Bill's force):
Work = force × distance
Bill's force is 40 N, and the distance the effort force moves is 0.6 m. Therefore, the work done by Bill's force is:
Work_effort = 40 N × 0.6 m
2. Find the work done by the resistance force (boulder's weight):
Work = force × distance
The weight of the boulder is given as its mass multiplied by the acceleration due to gravity (g = 9.8 m/s²). The distance the resistance force moves is 0.1 m. Therefore, the work done by the resistance force is:
Work_resistance = (20 kg × 9.8 m/s²) × 0.1 m
3. Calculate the efficiency:
Efficiency = (Work_effort / (Work_effort + Work_resistance)) × 100%
Now we can substitute the values into the formula and calculate the efficiency.
Bill used a first class lever to lift a heavy boulder that had a mass of 20 kg. He
pushed down on one end of the lever with 40 N of force. This end of the lever when down 0.6 m. This resulted in the boulder lifting 0.1 m. Calculate the efficiency of the lever.