Question

How is the kinetic energy of a moving car affected if
》its mass is tripled.
》its velocity become 1/4th​

Answer 1

Answer:

1. its mass is tripled then kinetic energy tripled

2.its velocity become 1/4th​ then kinetic energy become 1/16

Explanation:

we have formula for kinetic energy

$K= \frac{1}{2}mV^{2}$

means that

$K\alpha m\\K\alpha V^{2}$

1. its mass is tripled

we have K₁ $\alpha$ m

if mass tripled 3m

K₂$\alpha 3m$

divide

K₂/K₁= 3m/m

K₂/K₁ = 3

K₂ = 3K₁

2. its velocity become 1/4th​

we have

K₁ $\alpha$ V²

velocity become V/4 then

K₂ $\alpha$ (V/4)²

K₂ $\alpha$ V²/16

divide

K₂/K₁ = (V²/16)/ V²

K₂/K₁ = 1/16

K₂ = (1/16)K₁

Answer 2

Answer:

If the mass is tripled, the new kinetic energy of the car will be three times greater than that of the previous case.

If velocity becomes 1/4th, the new kinetic energy of the car will be 1/16 times that in the previous case.

Explanation:

The kinetic energy of a body of mass 'm' moving with a velocity 'v' is given by the equation:

K.E = mv²/2

If the mass of the car is tripled, then the mass will change as m' = 3m.

Then the new kinetic energy will be, K.E' = m'v²/2

                                                                     = 3 mv²/2

                                                              K.E' = 3 × K.E

So the new kinetic energy of the car will be three times greater than that of the previous case.

If the velocity of the car becomes 1/4th, then we may write 'v' as v' = v/4.

Now the new kinetic energy will be, K.E' = m(v/4)²/2

                                                                    = 1/16 × mv²/2

                                                             K.E' = 1/16 × K.E

The new kinetic energy of the car will be 1/16 times that in the previous case.