Question

how does kinetic energy of a moving ball change if its speed is reduced to half of original speed take mass of the ball is equal to 4 kg and original speed is equal to 20m/s

Answer 1

Kinetic energy will become 1/4 times the previous one.

Since Kinetic energy=1/2*m*v^2

M=mass of object and v=velocity of object.

Answer 2

$\huge \bold{ANSWER}$

◼The energy possessed by a body due to its state of motion is called kinetic energy.

◼The kinetic energy possessed by a body is equal to the amount of work which the moving body can do before coming to rest. It can be calculated by the amount of work done by opposing force to stop the body.

So, we can find kinetic energy by applying formula,

K=$\frac{1}{2} \times mass \times {velocity}^{2}$

Given,

mass = 4kg

velocity =20m/s

On placing values the kinetic energy will be,

K=$\frac{1}{2} \times 4 \times {20}^{2}$

K=$\frac{1}{2} \times 4 \times {20 \times 20}$

K = 800J.

According to question,

speed is reduced to half so,

$= \frac{20}{2}$

=10 m/s.

while mass of a body always remains same,

So,

K=$\frac{1}{2} \times mass \times {velocity}^{2}$

Given,

mass = 4kg

velocity =10m/s

On placing values the kinetic energy will be

K=$\frac{1}{2} \times 4 \times {10}^{2}$

K=$\frac{1}{2} \times 4 \times {10 \times 10}$

K = 200J.

So, the kinetic energy will become one fourth of the original kinetic energy.