Question

A boy weighing 40 kg carries a box weighing 20 kg to the top of a building 15 m high in 25 seconds. Calculate the power. (g = 10 m/ )

Answer 1

$\Huge{\underline{\underline{\blue{\mathfrak{Answer :}}}}}$

$\Large{\purple{\sf{Given :}}}$

• Boy Weight = 40 kg
• Box weight = 20 kg
• Height of building (h) = 15 m
• Time (t) = 28 seconds
• Gravitational Force(g) = 10 m/s²

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$\LARGE{\orange{\sf{To \: Find :}}}$

Power of boy.

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$\LARGE{\pink{\sf{Solution :}}}$

Total weight = 40 kg + 20 kg

Total Weight = 60 kg

But, Weight = Mass * g

$\large \implies {\boxed{\sf{Mass \: = \: \frac{Weight}{g}}}}$

→ Mass = 60/10 ⟹ 6 kg

$\Large \leadsto {\sf{Mass \: (m) \:= \: 6 \: kg}}$

We have formula :-

$\LARGE{\boxed{\boxed{\green{\tt{Power \: = \: \frac{Work}{Time}}}}}}$

Work Done = mgh

→ Work Done = (6)(10)(15)

→ Work Done = 6 * 150

→ Work Done = 900 J

(Now Put Value in above formula)

$\Large \leadsto {\sf{Power \: = \: \displaystyle \frac{\cancel{900}}{\cancel{25}}}}$

$\Large{\boxed{\red{\sf{Power \: = \: 36 \: W}}}}$