Question

calculate the work done in kilo joules in lifting a mass of 10kg (at a steady velocity) through a vertical height of 10m?

Answer 1

W=F*S
since,F=m*a
here, a=(-g) since, the body is moving away from the centre.
so, W=m*(-g)*S
W=10*(-9.81)*10
W=-981 j
W=-981/1000 kj
W=-0.981 kj
negative (-) sign represents the opposite direction.

Answer 2

Concept:

Work done by any object can be defined as

w = mgh

Where m = mass of the object, g = acceleration due to gravity, and h = height from the ground.

Given:

Mass, m = 10 kg

Vertical height, h = 10 m

Find:

Work done in kilojoules.

Solution:

Work done,

w = mgh

Taking g = 10 m/s²,

w = mgh

w = (10)(10)(10)

w = 1000J

Dividing the work done in joules by 1000 to convert it in kilojoules,

w = 1  kJ

Hence, the work done in lifting a mass of 10kg through a vertical height of 10m is 1 kJ.

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