Question

9. A porter lifts a luggage of 15 kg from the ground and puts it on his head 15 m above the
around. Calculate the work done by him on the luggage.​

Answer 1

Answer :-

2250J

Explanation :-

Given :

• Mass of luggage (m) = 15kg

• Displacement (s) = 15m

• Gravitational acceleration (g) = 10m/s^2

To Find :

• Work done (W) = ?

Solution :

Work done in lifting an object, W = gravitational potential energy = mgh

Put their values and solve it.

$\sf{}\Rightarrow 15kg\times 10m/s^2 \times 15m$

$\sf{}\Rightarrow 2250J$

Therefore,work done by him on the luggage is equal to 2250J

Know more

Work: Work is said to be done when force produces motion along its direction. Work = Force × Displacement

We know that, work done = Force × displacement

W = F × s

Therefore, Work done, W = F × h (displacement = height)

Where, ‘h’ is the displacement of the object. Since, the object is displaced at a height, therefore, ‘h’ is taken at the place of ‘s’.

Or, W = mgh (since, F = mg)

Answer 2

Mass of the luggage = 15 kg

Displacement took place = 15 m

Let us assume that,

g = 10 m/s² [Can be used in case of solving equations]

We know,

W = F × s

Here, F = w (Weight)

$\longrightarrow$ W = w × s

$\longrightarrow$ W = mg × s

$\longrightarrow$ W = (15 kg)(10 m/s²)(15 m)

$\longrightarrow$ W = 2250 Nm

$\longrightarrow$ W = 2250 J (Answer)