Question

Calculate the power of a crane in watts, which lifts a mass of 100 kg to a height of 10 m in 20s.

Answer 1

power=work done/time
work done=mgh
=100×10×10
=10000 J
power =work done/time
power=10000/20
power=500 watt

Answer 2

Answer:

The power of a crane is 490 watt.

Explanation:

Given that,

Mass m = 100 kg

Height h = 10 m

Time t = 20 s

We know that,

The power is defined as:

$P=\dfrac{W}{t}$....(I)

Here, W= work done

t= time

We know that,

The work done is

$W= mgh$

$W= 100\times9.8\times10$

$W= 9800\ J$

Put the value of W in equation (I)

The power is

$P=\dfrac{9800}{20}$

$P= 490\ watt$

Hence, The power of a crane is 490 watt.