Question

If the mass were to increase 25 times (from bicycle to motorcycle) what would happen to the kinetic energy?

A. decrease 25 times

B. stay the same

C. increase 25 times

D. increase 50 times

Answer 1

Given :-

• Mass of the body is increases by 25 times

To find :-

• Kinetic energy

SOLUTION :-

Let the Kinetic energy of the body with mass "m" and velocity "v" =

$KE_1 = \dfrac{1}{2}mv^2$

As the mass of the body increases 25 times of the original mass = 25m  and the velocity "v" So,

$K.E_2 = \dfrac{1}{2} (25m) v^2$

$\dfrac{K.E_1}{K.E_2} =\dfrac{\dfrac{1}{2} mv^2}{\dfrac{1}{2}25m v^2 }$

$\dfrac{K.E_1}{K.E_2} =\dfrac{\not{\dfrac{1}{2}} \not{m}\not{v^2}}{\not{\dfrac{1}{2}}25\not{m }\not{v^2 }}$

$\dfrac{K.E_1}{K.E_2} =\dfrac{1}{25}$

$K.E_2 = 25K.E_1$

So, it increases 25 times {c}

Know more :-

• K.E = 1/2 mv²

Kinetic energy:- The energy possessed by the virtue of motion is known as Kinetic energy.

☆ Kinetic energy is directly proportional to mass of the body and velocity of the body

☆ Kinetic energy is always positive beacuse as mass of the body can't be negative if velocity be negative it beacomes positive as the square is there

☆ Kinetic energy depends on frame of reference