Question

a motor works 20J for 25s .calculate the power of motor​

Answer 1

We know that Power = Work done/Time

GIVEN,

                Work done = 20 J

                  Time = 25s

THEN,

            Power = 20/25

                        = 4/5 = 0.8 watt

Answer 2

0.8 watt is the required answer.

GIVEN:

• Work , w = 20 J
• Time, t = 25 seconds

TO FIND:

Power of the motor, p

FORMULA:

Power, p = w/t

SOLUTION:

P = w/t

P = 20/25

P = 4/5

P = 0.8 watt

ANSWER:

Power of the motor is 0.8 watt.

IMPORTANT POINTS:

• Power is defined as the rate of doing work.

• Power is equal to the ratio of work done to the time.

• Power is also equal to the dot or scalar product of force and velocity. p = f • v

• Power is a scalar quantity.

• It has magnitude only. It does not have direction.

• Its unit is watt or W or J/s or kgm²/s³

• Dimensional formula for power is [M L² T^-3 ]

• The commercial unit of power is kilo watt hour.

• Horse power is also a unit of power.

• 1 Hp = 746 watt