Question

A moving body of 30 kg has 60 joule of kinetic energy calculate the speed!

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Answer 1

Answer:

Hi,

.$\huge\color{pink}\boxed{\colorbox{Black}{Answer}}$

Step-by-step explanation:

K.E = 1/2 * m* v²

where,

K.E = kinetic energy of a body

m = mass of the body

1. v = Velocity of the body

• From Given We have

• K.e=60Joule

• m = 30 kg

• ⇒ 60 = 1/2 x 30 × v² X

• ⇒ 2 x 60 30 × v²

• ⇒120 = 30 x v²

⇒4=v²

Required Answer

... v = 2 m/s

$\:$

Answer 2

Answer:

Here, the concept of kinetic energy has been used. We see that we need to calculate the speed of the body when mass and kinetic energy of the body is given. We can calculate the velocity of the moving body by using formula of kinetic energy. Equating all the values in formula and after further simplifying, we'll get the velocity.

Formula used:

Kinetic energy is directly proportional to the mass of the body and to the square of it's velocity. That is,

$\bullet\quad\boxed{\sf{Kinetic\: Energy,\: K.E.}=\bold{\dfrac{1}{2}\times m {v}^{2}}}$

• m = Mass of the body
• v = Velocity of the body

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Solution:

Given,

» Mass of the moving body = m = 30 kg

» Kinetic energy of the body = K.E. = 60 J

From the formula of kinetic energy, we get:

$\; \; \; \longrightarrow\quad\tt{Kinetic\; energy\:=\: \dfrac{1}{2}\:\times\: m\: {v}^{2}}$

Equating all the values, we get:

$\; \; \; \longrightarrow\quad\tt{60\: =\: \dfrac{1}{2}\: \times\: 30\:\times\: {v}^{2}}$

Performing multiplication in RHS.

$\; \; \; \longrightarrow\quad\tt{60\: =\: \dfrac{30}{2}\:\times\: {v}^{2}}$

Performing division.

$\; \; \; \longrightarrow\quad\tt{60\: =\: 15\: \times \: {v}^{2}}$

Transposing 15 from RHS to LHS. It's arithmetic operator will get change.

$\; \; \; \longrightarrow\quad\tt{\dfrac{60}{15}\: =\: {v}^{2}}$

Performing division.

$\; \; \; \longrightarrow\quad\tt{{v}^{2}\: =\: 4}$

Transposing square from LHS to RHS.

$\; \; \; \longrightarrow\quad\tt{v\: =\: \sqrt{4}}$

Equating value of √4 as 2.

$\; \; \; \longrightarrow\quad\underline{\boxed{\tt{v}\:=\bold{\purple{2\; m/s}}}}$

Therefore, the required answer is:

❝ The velocity or speed of the moving body is 2 m/s. ❞