Question

a body of mass 60 kg has a momentum of 3000 kg.m/s , calculate the kinetic energy and speed of the body.
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Answer 1

EXPLANATION :-

GIVEN :-

⇒ Mass (m) = 60 Kg

⇒ Momentum (p) = 3000 Kgm/s

TO FIND :-

⇒ Kinetic energy (K.E)

⇒ Speed of the body (v)

SOLUTION :-

Relationship between momentum & kinetic energy :

⇒ p = √2mk or K = p²/2m

Hence :

⇒ K = (3000)²/2(60)

⇒ K = 9000000/120

⇒ K = 90/12 × 10⁴

⇒ K = 7.5 × 10⁴ J

Momentum of a body is the product of its mass & velocity :

⇒ p = mv

Hence :

⇒ 3000 = 60(v)

⇒ 3000 = 60v

⇒ v = 3000/60

⇒ v = 50 m/s

∴,

The kinetic energy is 7.5 × 10⁴ J.

The speed is 50 m/s.

Answer 2

⇝GIVEN :

• Mass = 60kg
• Momentum = 3000kgm/s

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⇝TO FIND :

• Kinetic energy = ?

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⇝FORMULA USED :

${\red{\bigstar \: \: {\orange{\underbrace{\underline{\overbrace{\overline{\mathfrak{Kinetic \: Energy = \frac{ {p}^{2} }{2m} }}}}}}}}}$

❒Here,

P = Momentum

M = Mass

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⇝SOLUTION :

❒Here,

Momentum = 3000 kgm/s

Mass = 60kg

❒Now,

${\mapsto{\bf{Kinetic \: Energy = \frac{ {p}^{2} }{2m} }}}$

${\leadsto{\sf{Kinetic\:Energy = \frac{ ({3000})^{2} }{2 \times 60} }}}$

${\leadsto{\sf{{\cancel\frac{9000000}{120} }}}}$

${\purple{\leadsto{\sf{ 75,000 J}}}}$

❒So,

${\red{\underline{\purple{\underline{\boxed{\sf{Final \: K.E = 7.5 \times {10}^{4} \: joules }}}}}}}$

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