The time taken to perform 640 J of work at a rate of 32 W is ________.

Question

Question

Answer 1

Option 3 is correct.

CONCEPT:

Work done (W): The magnitude of the force multiplied by the distance moved by the object in the direction of the applied force is called work done.
- The unit of work is the joule (1 J = 1 Nm).
- Work done on an object by a force would be zero if the displacement of the object is zero.
- It is the dot product of force and displacement.
- It is a Scalar quantity.

W = F.s cosθ

Where F is applied force, s is displacement in the direction of force and θ is angle between force and displacement.

Power: It is defined as the rate of doing work/
- The SI unit of power is Watt. (1 Watt = 1 Joule/second).

Power (P) = work (W)/time (t).

CALCULATION:

Given that:

Work done (W) = 640 J

Power (P) = 32 W

So time taken (t) = W/P = 640/32 = 20 sec.

So option 3 is correct.