Rate of doing work is called ________.
Power
Power is defined as the rate of doing work, i.e. the amount of work done per unit time.
It is measured in watts (W = J/s) in SI.
Energy is the capacity to do work, pressure is force per unit area and force has its own SI unit (Newton).
Hence, Power.
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.
A boy of mass 50 kg climbs 42 steps in 10 s. If each step is 15 cm high, find his power. Take \(g = 10\text{ms}^{-2}\).
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 \(g = 10 \text{ ms}^{-2}\).
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 )