A car weighs 1000 kg. It is moving with a uniform velocity of 72 km/h towards a straight road. The driver suddenly presses the brakes. The car stops in 0-2 s. The retarding force applied on the car to stop it is

Correct option is D

Correct Answer: D (100 kN)

Explanation:

1. Given Data:

   • Mass of the car: 1000 kg
   • Initial velocity: 72 km/h = 20 m/s (converted from km/h to m/s)
   • Final velocity: 0 m/s (car stops)
   • Time to stop: 0.2 seconds

2. Step 1: Calculate Deceleration:Acceleration (a) = (Final velocity - Initial velocity) / Time
   a = (0 - 20) / 0.2 = -100 m/s²

3. Step 2: Calculate Retarding Force:Force (F) = Mass × Acceleration
   F = 1000 × (-100) = -100,000 N

The magnitude of the retarding force is 100,000 N, which is equivalent to 100 kN.