Question

Calculate the work done required to stop a car of mass 1000kg moving at a velocity of 10 m/s will be​

Answer 1

You are being asked to deploy this equation:

force = mass X acceleration, or f = m*a

m = 1000 kg

velocity 45 km/hr = 12.5 m/s so

acceleration a = -2.5 m/s^2 Therefore

f = m*a = 1000 * -2.5 = -2500 newtons

Answer 2

Answer:

Work done to stop the car is -50,000 J.

Explanation:

Mass of the car, m = 1000 Kg

The initial velocity of the car, u = 10 m/s

The car has been stopped. So its final velocity, v = 0 m/s

The initial kinetic energy of the car,

K.E₁ = (mu²) / 2

K.E₁ = (1000 × 10²) / 2

K.E₁ = 1,00,000 / 2

K.E₁ = 50,000 J

The final kinetic energy of the car will be zero since it has stopped the motion.

K.E₂ = 0 J

From the work-energy theorem, we know that the change in kinetic energy is equal to the work done.

∴ Work done to stop the car, W = Final K.E - Initial K.E

                                                W = K.E₂ -K.E₁

                                                W = 0 - 50000

                                                W = -50,000 J