Read the passage given below and answer the following questions from 1 to 5.
Power is defined as the time rate at which work is done or energy is transferred. The average power of a force is defined as the ratio of the work, W, to the total time t taken
P
av = W/t
The instantaneous power is defined as the limiting value of the average power as time interval approaches zero.
P = dw/dt
The work dW done by a force F for a displacement dr is dW = F.dr. The instantaneous power can also be expressed as
P = F.dr/dt
P = F.v
Where v is the instantaneous velocity when the force is F. Power, like work and energy, is a scalar quantity. Its dimensions are [ML
2 T
-3]. In the SI, its unit is called a watt (W). The watt is 1 J s
-1. The unit of power is named after James Watt, one of the innovators of the steam engine in the eighteenth century. There is another unit of power, namely the horse-power (hp)
1 hp = 746W
This unit is still used to describe the output of automobiles, motorbikes.
- The time rate at which work is done or energy is transferred is called as:
- Energy
- Force
- Power
- None of these
- Limiting value of power as time interval approaches zero is called as:
- Average power
- Instantaneous power
- Both a and b
- None of these
- Power is directly proportional to:
- Force
- Velocity
- Both
- None of these
- Define instantaneous power. Give its SI unit and dimensions.
- 1 horse power is equal to how many watt?
