Question

The kinetic energy of a car is 8 × 106 J as it travels along a horizontal road. How much power is required to stop the car in 10 s?

Answer 1

Answer:

The power required to stop the car =  8 × 10⁵ watt.

Explanation:

Kinetic Energy: This is the energy of a body in motion. The S.I unit of energy is Joules (J).

Power: These is defined as time rate of doing work, or it can be defined as the time rate of transfer of energy. The S.I unit of power is Watt (W).

Mathematically, power can be expressed as

Power = Energy/time

P = E/t................. Equation 1

Given: E = 8×10⁶ J, t = 10 s

Substituting these values into equation 1,

p = 8×10⁶/10

p = 8 × 10⁵ watt.

Therefore the power required to stop the car =  8 × 10⁵ watt.