Question

If a car of mass 900 kg stops from a speed of 90kmph in just 10 seconds, then the force responsible for stopping the car is _______ (in N)

Answer 1

Given:-

• Mass of car ,m = 900kg

• Initial velocity ,u = 90km/h

• Final velocity ,v = 0m/s

• Time taken ,t = 10s

To Find:-

• Force responsible for stopping the car,F.

Solution:-

Unit Conversion

→ 90km/h = 90×5/18 = 25m/s

Firstly we have to calculate the acceleration of the car.

Rate of change of velocity at per unit time is called acceleration.

→ a = v-u/t

Substitute the value we get

→ a = 25-0/10

→ a = 25/10

→ a = 2.5m/s²

Now we know that Force is the product of mass and acceleration

→ F = m×a

Substitute the value we get

→ F = 900×2.5

→ F = 2250N

∴ The force responsible for stopping car is 2250 Newton.