Advertisements
Advertisements
प्रश्न
Choose one or more correct alternatives.
Power is a measure of the ______.
- The rapidity with which work is done.
- Amount of energy required to perform the work.
- The slowness with which work is performed.
- Length of time.
उत्तर
Power is a measure of the rapidity with which work is done and the slowness with which work is performed.
APPEARS IN
संबंधित प्रश्न
A pump on the ground floor of a building can pump up water to fill a tank of volume 30 m3 in 15 min. If the tank is 40 m above the ground, and the efficiency of the pump is 30%, how much electric power is consumed by the pump?
The blades of a windmill sweep out a circle of area A.
- If the wind flows at a velocity v perpendicular to the circle, what is the mass of the air passing through it in time t?
- What is the kinetic energy of the air?
- Assume that the windmill converts 25% of the wind’s energy into electrical energy, and that A = 30 m2, v = 36 km/h and the density of air is 1.2 kg m–3. What is the electrical power produced?
Rajan exerts a force of 150 N in pulling a cart at a constant speed of 10 m/s-1. Calculate the power exerted.
Power P= ............ /time taken.
1 H.P. = .........
The expression of power P is
It takes 20 s for a girl A to climb up the stairs while girl B takes 15 s for the same job. Compare the work done .
An electric heater of power 3 kW is used for 10 h. How much energy does it consume? Express your answer in
- kWh,
- joule.
An electric pump has 2 kW power. How much water will the pump lift every minute to a height of 10 m?
Define power.
What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R so that it can complete the loop?.
An engine pumps up 200 kg of water through a height of 20 m in 10 seconds. If the efficiency of the engine is 80%. Calculate the power of the engine.
Calculate the power of a crane in watts, which lifts a mass of 100 kg to a height of 10 m in 20s.
The average work done by a human heart while it beats once is 0.5 J. Calculate the power used by heart if it beats 72 times in a minute.
A man is throwing bricks of mass 2 kg onto a floor from a height of 2 m. Bricks reach the floor at a speed `2sqrt(10)` m/s. Man throws 10 bricks in a minute. If the power of man is W watt then `3/10` W is equal to ______ W.
Sand is being dropped from a stationary dropper at a rate of 0.5 kgs-1 on a conveyor belt moving with a velocity of 5 ms-1. The power needed to keep belt moving with the same velocity will be ______.
Unit of power used in mechanical engineering is ______.
Name the quantity which is measured in kW.