Question

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$\huge{FOR\:YOU}$
calculate the work done by a boy in lifting a 10 kg laptop from the ground and keeping it on a shelf 1.5 m high.
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Answer 1

Answer :-

Therefore the work done by a boy in lifting a laptop from the ground and keeping it on a shelf 1.5 m high is 147 J.

Solution :-

Mass of the laptop (m) = 10 Kg

Force of gravity acting on the laptop = mg

= 10 * 9.8

Since Acceleration due to gravity (g) = 9.8 m/s²

= 98 N

Force of gravity acting on the laptop = 98 N

Boy will apply a force emwhich iqual to the force of gravity acting on the object in order to lift it.

So, Force applied by the boy on the laptop (F) = 98 N

Displacement of the laptop in the direction of force (S) = 1.5 m

We know that

Work done = F * S

= 98 * 1.5

= 147 J

Therefore the work done by a boy in lifting a laptop from the ground and keeping it on a shelf 1.5 m high is 147 J.

Answer 2

Answer:

Explanation: Here the boy is lifting an object and keeps in on shelf. Therefore he places the object at a place which is higher than the ground. Due to this the object gains energy(capacity to do work). As this energy is stored energy and the object is placed somewhere above the ground the energy is gravitational potential energy. As we all know (if u don't know, know it here!!!) the formula for calculating gravitational potential energy in mgh. We can easily caculate the work done as the capacity to do work is energy.

CALCULATIONS-

Mass(m)- 10 kg

Acceleration due to gravity (g)-

9.8 m/s²

Height- 1.5m

Potential energy (E.P.)-?

E.P.=mgh

=10×9.8×1.5

E.P.=147 J