Question

Does the kinetic energy of a car change more when it accelerates from 27 km/h to 37 km/h or when it accelerates from 37 km/h to 47 km/h?
1) More information is needed.

2) No difference

3) From 37 km/h to 47 km/h

4) From 27 km/h to 37 km/h

Answer 1

Answer:

3) From 37 km/h to 47 km/h

Explanation:

Kinetic Energy: This is the energy posses by a body in motion. The Unit of kinetic energy is joules. And it is expressed mathematically as,

Ek = 1/2mv².................... Equation 1

ΔEk = 1/2m(v₂² - v₁²)...................... Equation 2

Where ΔEk = change in kinetic energy,  m = mass of the body, v₁ = initial velocity, v₂ = final velocity of the body.

Note: The mass of the car is constant in both cases.

When the body accelerate from 27 kh/h to 37 km/h

ΔEk₁ = 1/2m(37²-27²)

ΔEk₁ = 1/2m(640)

ΔEk₁ = 320m J.

When The body accelerate from 37 km/h to 47 km/h

ΔEk₂ = 1/2m(37²-47²)

ΔEk₂ = 1/2m(840)

ΔEk₂ = 420m J

From the above,

ΔEk₂ > ΔEk₁.

Hence the correct option is 3) From 37 km/h to 47 km/h