Question

a body of mass 5 kg is moving with a velocity 10 m/s. find its kinetic energy. find the ratio energy of initial kinetic energy and final kinetic energy if (a) its mass is doubled (b) its velocity is made three times.​

Answer 1

$\huge\boxed{\underline{\mathfrak{Answer}}}$

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.