Question

What is the work done in lifting a body of mass 800kg to a height of 15m provided the gravitational pull is 10m/second square

Answer 1

Given :

➳ Mass of body = 800kg

➳ Height = 15m

➳ Acc. due to gravity = 10m/s²

To Find :

➛ Work done in lifting the body.

Concept :

➜ This question is completely based on the concept of Work-Energy theorem. (WET)

➜ As per WET, Work done is always equal to change in energy.

➜ Potential energy of body of mass m at a height of h is given by

✭ U = mgh

Calculation :

⇒ W = ΔU = Uf - Ui

⇒ W = mgh - 0

⇒ W = 800 × 10 × 15

⇒ W = 1,20,000J = 120kJ

Answer 2

$\huge\sf\pink{Answer}$

☞ Work Done = 120 KJ

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$\huge\sf\blue{Given}$

✭ Mass of the object = 800 kg

✭ Height reached = 15 m

✭ Gravitational Acceleration = 10 m/s

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$\huge\sf\gray{To \:Find}$

◈ The work done?

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$\huge\sf\purple{Steps}$

Here your Answer is equal to the change in the energy of the body,that is,

➝ $\sf Work = \triangle U$

That is,

➝ $\sf Work = U_f - U_1$

➝ $\sf Work = mgh-0$

$\sf\bigg\lgroup P_{eg} = mgh\bigg\rgroup$

Where,

$\quad$◕ m = Mass

$\quad$◕ G = Gravitational Acceleration

$\quad$◕ h = Height Attained

Substituting the given values,

➳ $\sf Work = 800 \times 10 \times 15$

➳ $\sf\red{ Work = 120000 J}$

»» 1 KJ = 1000 J

»» $\sf 120000 J = \dfrac{120000}{1000}$

»» $\sf \orange{Work = 120 KJ}$

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