Question

A 75 kg person lifts a 25 kg object to a height of 10 meters in 5 minutes. What is the power used?

• A. 7.33 J/S
• B. 8.33 J/S
• C. 9.33 J/S
• D. 10.33 J/S

Hint:

Power is the rate of doing work, and the formula to calculate power is \( P = \frac{W}{t} \).

Answer 1

The Correct Option is B

Power is the rate at which work is done, and it is given by the formula: \[ P = \frac{W}{t} \] where \( P \) is power, \( W \) is work done, and \( t \) is time. The work done to lift the object is given by: \[ W = mgh \] where \( m \) is the mass of the object, \( g \) is the acceleration due to gravity, and \( h \) is the height. Given: - Mass \( m = 25 \, \text{kg} \) - Height \( h = 10 \, \text{m} \) - Acceleration due to gravity \( g = 10 \, \text{m/s}^2 \) - Time \( t = 5 \, \text{min} = 300 \, \text{seconds} \) Now, calculate the work done: \[ W = 25 \times 10 \times 10 = 2500 \, \text{J} \] Now, calculate the power: \[ P = \frac{2500}{300} = 8.33 \, \text{J/S} \]