Question

a body of mass 25 grams as a momentum of 0.4 40 km per find its kinetic energy

I want explaination​

Answer 1

Answer:

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Answer 2

Answer:

Given :-

• A body of mass 25 g has a momentum of 0.40 kg m/s.

To Find :-

• What is the kinetic energy of a body.

Solution :-

First, we have to find the velocity of a body :

Given :

• Momentum (p) = 0.40 kg m/s
• Mass (m) = 25 g = 0.025 kg

According to the question by using the formula we get,

$\implies \sf\boxed{\bold{p =\: mv}}$

where,

• p = Momentum in (kg m/s)
• m = Mass in (kg)
• v = Velocity in (m/s)

So, by putting those values we get,

$\implies \sf 0.40 =\: 0.025 \times v$

$\implies \sf 0.40 =\: 0.025v$

$\implies \sf \dfrac{0.40}{0.025} =\: v$

$\implies \sf 16 =\: v$

$\implies \sf\bold{v =\: 16\: m/s}$

Hence, the velocity of a body is 16 m/s .

Now, we have to find the kinetic energy of a body :

Given :

• Mass (m) = 0.025 kg
• Velocity (v) = 16 m/s

According to the question by using the formula we get,

$\implies \sf\boxed{\bold{K.E. =\: \dfrac{1}{2} mv^2}}$

where,

• K.E. = Kinetic Energy in (J)
• m = Mass in (kg)
• v = Velocity in (m/s)

So, by putting those values we get,

$\implies \sf K.E. =\: \dfrac{1}{2} \times (0.025) \times (16)^2$

$\implies \sf K.E. =\: \dfrac{1}{2} \times (0.025) \times (16 \times 16)$

$\implies \sf K.E. =\: \dfrac{1}{2} \times 0.025 \times 256$

$\implies \sf K.E. =\: \dfrac{1}{2} \times 6.4$

$\implies \sf K.E. =\: \dfrac{1 \times 6.4}{2}$

$\implies \sf K.E. =\: \dfrac{6.4}{2}$

$\implies \sf\bold{\underline{K.E. =\: 3.2\: J}}$

$\therefore$ The kinetic energy of a body is 3.2 J .