Question

A car has a kinetic energy of 2000 J. What will be its kinetic energy if its speed is doubled?​

Answer 1

Answer:

8000 J

Explanation:

According to formula of kinetic energy,

$\boxed{\huge\sf{Kinetic \ energy = \dfrac{1}{2} mv^2}}$

Thus , when the kinetic energy is 2000 J,

$\sf KE_0 = \dfrac{1}{2}mv^2$

v = velocity of car, m = mass of car

Now , when velocity is doubled,

v'(new) = 2v

Thus,

$\sf KE = \dfrac{1}{2} m (2v)^2$

$\sf KE = \dfrac{1}{2} 4mv^2$

As , $\dfrac{1}{2} mv^2 = 2000 J$,

so,

$\sf KE = 4 \times 2000$

$\sf KE = 8000 \ j$

Thus , when speed is doubled , kinetic energy becomes 8000 J

Answer 2

Given Information:

A car has a kinetic energy of 2000 J. What will be its kinetic energy if its speed is doubled?

Solution:

Suppose m and v is the mass and speed of the car.

So,we know that,

Kinetic energy = 1/2mv²

2000 = 1/2mv²

Given that, speed is doubled.So, v will becomes 2v.Then kinetic energy will be,

K.E = 1/2m(2v)²

K.E = 1/2 × 4 × mv²

K.E = (4 × 2000)J

K.E = 8000J

Therefore, 8000J is the kinetic energy if its speed is doubled.