Question

A body of mass 5 kg is moving with a velocity 10 mg-1. Find the ratio of initial kinetic
final kinetic energy if its mass is doubled​

Answer 1

$\huge{\underline{\underline{\mathrm{Answer \colon}}}}$

From the Question,

• Initial Mass,m = 5kg

• Velocity of the body,v = 10m/s

We Know that,

$\huge{\sf{K = \frac{1}{2}mv{}^{2}}}$

Case 1

• Mass is the same

Putting the values,we get:

$\sf{{K}_{i} = \frac{1}{2}.5.10.10} \\ \\ \rightarrow \ \boxed{\sf{{K}_{i} = 250J}}$

Case 2

• Mass is doubled » M = 10Kg

Putting the values,we get:

$\sf{{K}_{f} = \frac{1}{2}.10.10.10} \\ \\ \rightarrow \ \boxed{\sf{{K}_{f} = 500J}}$

Now,

$\sf{{K}_{i} \colon {K}_{f} = 250 \colon 500} \\ \\ \implies \ \huge{\boxed{\bold{\sf{{K}_{i} \colon {K}_{f} = 1 \colon 2 }}}}$

The ratio of their kinetic energies is 1:2

Answer 2

Answer:

Explanation:

Given :-

Mass of moving object, m = 5 kg

Velocity of moving object,

To Find :-

Ratio of initial Kinetic energy.

Formula to be used :-

$\boxed { \underline { K =\frac{1}{2}mv^2}}$

Solution :-

At we will find, Initial Kinetic energy

Putting all the values, we get

$\implies K =\frac{1}{2}mv^2$

$\implies k=\frac{1}{2}\times5\times10\times10$

$\implies k=250 \: J$

Then, final kinetic energy when mass is doubled,

Mass of moving object, m = 10 kg

Putting all the values, we get

$\implies K =\frac{1}{2}mv^2$

$\implies k=\frac{1}{2}\times10\times10\times10$

$\implies k =500 \: J$

Hence, the ratio initial and final kinetic energy is 1 : 2.