A boy of mass 50 kg climbs 42 steps in 10 s. If each step is 15 cm high, find his power. Take \(g = 10\text{ms}^{-2}\).
315 W
Total height = 42 × 0.15 = 6.3 m.
Work done = mgh = 50 × 10 × 6.3 = 3150 J.
Power = work/time = 3150/10 = 315 W.
Note the unit — power is measured in watts.
Hence, 315 W.
Similar Questions
A device uses 1 kilowatt (kW) of power for 1 hour. How much energy does it consume?
Student A takes 20 seconds, while student B takes 40 seconds to complete the same amount of work. Which of the following statements is correct in connection to A and B?
If a girl of weight 40 N climbs a rope with a power of 160 W for 20 seconds, up to what height can she reach?
A boy of mass 50 kg runs up a staircase of 40 steps in 10 s. If the height of each step is 15 cm, find his power. Take \(g = 10 \text{ ms}^{-2}\).
A boy of mass 50 kg climbs 43 steps in 10 s. If each step is 15 cm high, find his power. Take \(g = 10 \text{ ms}^{-2}\).
A 100 W electric bulb is used for 8 hours a day. The energy used by the bulb in 5 days is _____ units.
What is the SI unit of Power?
A factory manager is comparing two machines that perform the same task. Machine A takes more time to complete the task than Machine B. Based on the definition of power, which factor should the manager consider to determine which machine is more powerful?
A boy of mass 50 kg runs up a staircase of 40 steps in 10 s. If the height of each step is 15 cm, find his power. Take \(g = 10 \text{ ms}^{-2}\).
Rate of doing work is called ________.
Important Questions from Power
Express the power dissipated in a 100 Ω resistor in dB relative to 1 mW, when the voltage across the resistor is 1.0 Vrms
An elevator weighing 500 kg is to be lifted up at a constant velocity of 0.25 m/s. What would be the minimum horsepower of the motor to be used? G = 9.8 m/s2 and there is no frictional loss.
A man of mass 80 kg climbs up 4 m high stairs in 10 sec. Find the power spent by the man. (Take g = 10 m/sec2)
How many units of electric power will be consumed by 4 motors of 0.5 HP each in 8 hours?
The power of a water pump is 2 kW. The amount of water (in litres) it can raise in one minute to a height of 10 m will be :
(g = 10 m/s 2 )
