Question

1. A quantity of work of 1000 J is done in 2 seconds. The power utilised is O (a) 998 W O (b) 1002 W O (c) 2000 W O (d) 500 W​

Answer 1

Provided that:

• Work = 1000 J
• Time = 2 seconds

To determine:

• Power utilized

Solution:

• Power = 500 Watts

Using concept:

• Power formula

Using formula:

• P = W/t

Where, P denotes power, W denotes work done and t denotes time taken.

Required solution:

»»» Power = Work/time

»»» Power = 1000/2

»»» Power = 500 Watts

• Henceforth, option (d) is correct!

Additional information:

$\begin{gathered}\boxed{\begin{array}{c}\\ {\pmb{\sf{Some \: formulas!}}} \\ \\ \sf \star \: Power \: = \dfrac{Work \: done}{Time} \\ \\ \sf \star \: Time \: = \dfrac{Work \: done}{Power} \\ \\ \sf \star \: Power \times Time = Work \: done \end{array}}\end{gathered}$

Power = Force × Speed too! How?

$:\implies \sf Power \: = \dfrac{Work \: done}{Time} \\ \\ :\implies \sf Power \: = \dfrac{Force \times displacement}{Time} \\ \\ :\implies \sf Power \: = Force \times Velocity \\ \\ {\pmb{\sf{Henceforth, \: derived!}}}$

Answer 2

• Power is defined as the rate at which work is done per unit time.

• Here it is given that the work done is 1000 J and the time taken is 2 seconds

We have to find out power.

The power can be determined by the formula

Power = Work / Time

Putting the values in the formula,

Power = 1000/2

          = 500 Watts

The power will be 500 W.