Question

Calculate the kinetic energy of a car of mass 500kg moving with a velocity of

36km/h. Find the kinetic energy if the velocity of car doubles?​

Answer 1

Explanation:

Velocity of car, v = 36 km/hr = 36 × (5/18) = 10 m/s.Mass of car , m = 500 kg.Kinetic energy = (1/2) m v2 = (1/2) × 500 × 10 × 10 = 25000 J = 25 kJ.KInetic energy is proportional to square of velocity .If velocity doubles, Kinetic energy will becomes four times of its initial value.

Answer 2

Kinetic energy of car initially is 324000 joules and Kinetic energy when the velocity of car doubles is 1296000

Given:- Mass of car = 500kg

Velocity of car = 36km/h

To Find:- Kinetic energy of car initially and Kinetic energy if the velocity of car doubles.

Formula Used:- Kinetic Energy (K.E)= $\frac{1}{2}$m$v^{2}$

Solution:-

m = 500kg

v = 36km/h

K.E = $\frac{1}{2}$m$v^{2}$

K.E= $\frac{1}{2}$ * 500 * 36 *36

K.E = 324000 joules

Kinetic energy of car initially is 324000 joules

Now if the velocity of car doubles itself

Then v = 2v

So, K.E = $\frac{1}{2}$*m*$(2v)^{2}$

K.E = $\frac{1}{2}$*m*4$v^{2}$

K.E = 2m$v^{2}$

K.E = 2 * 500 * 36 *36

K.E = 1296000

So, Kinetic energy when the velocity of car doubles is 1296000