An effort force of 60N is applied to rise a load 100N. If the load is carried
through a distance of 20m and the effort moves through a distance of
40m using a lever, then,
a. What are AMA and VR of the machine
b. Calculate the Win and Wout
c. Find the amount of wasted energy
d. What is the efficiency of the machine
a. MA = L/E = 100/60 = 5/3.
VR = De/Dl = 40/20 = 2.
b. Wi = 60*40 =
Wo = 100*20 =
c. Wi-Wo =
d e = L/EVr = 100/(60*2) = 0.833 = 83.3 %.
To answer these questions, we need to understand the concepts of mechanical advantage (MA), velocity ratio (VR), work input (Win), work output (Wout), and efficiency.
a. Mechanical Advantage (MA) is determined by dividing the load (resistance) force by the effort force. In this case, the load force is 100N and the effort force is 60N. Therefore, the MA is calculated as:
MA = Load/Effort = 100N/60N = 5/3
Velocity Ratio (VR) represents the ratio of the distance moved by the effort force to the distance moved by the load force. In this case, the load moves 20m and the effort moves 40m. Thus, the VR is calculated as:
VR = Distance moved by effort/Distance moved by load = 40m/20m = 2
b. Work input (Win) is calculated by multiplying the effort force by the distance it moves. In this case, the effort force is 60N and the distance it moves is 40m. So, the Win is calculated as:
Win = Effort force × Distance moved by effort = 60N × 40m = 2400 Nm or 2400 Joules
Work output (Wout) is determined by multiplying the load force by the distance it moves. In this case, the load force is 100N and the distance it moves is 20m. Thus, the Wout is calculated as:
Wout = Load force × Distance moved by load = 100N × 20m = 2000 Nm or 2000 Joules
c. The amount of wasted energy can be determined by subtracting the Work output (Wout) from the Work input (Win). In this case,
Wasted energy = Win - Wout = 2400 Nm - 2000 Nm = 400 Nm or 400 Joules
d. Efficiency is determined by dividing the Work output (Wout) by the Work input (Win) and multiplying the result by 100 to express it as a percentage. In this case,
Efficiency = (Wout / Win) × 100
Efficiency = (2000 Nm / 2400 Nm) × 100
Efficiency = 0.8333 × 100
Efficiency ≈ 83.33%
Therefore, the efficiency of the machine is approximately 83.33%.