Question

A child has to complete 3600J of work in half a minute to lift a heavy load. How much power does he spend?

Answer 1

Answer:

P=120 watt

Explanation:

w = 3600J , t=1/2min = 30sec

P=?

P= w/t

P=3600/30

P=120 watt

Answer 2

Given

Work = 3600 J

Time = 30 s

To Find

Power

Solution

We know that

$\sf \longrightarrow P= \dfrac{W}{t}$

Here

• P = Power
• W = Work
• t = Time

Units

• P = Watt (W)
• W = Joule (J)
• t = seconds (s)

According to the question

We are asked to find power

Therefore

We must find "P"

Given that

Work = 3600 J

Time = 30 s

Hence

• W = 3600 J
• t = 30 s

Substituting the values

We get

$\sf \longrightarrow P=\dfrac{3600}{30} \ W$

$\sf \longrightarrow P=\dfrac{360}{3} \ W$

Therefore

$\sf \longrightarrow P=120 \ W$

Hence

Power = 120 W