Question

A motor car having a mass 50 kg moving with a velocity of 40 metre per second and it takes 2 seconds to stop after the brakes are applied the force exerted by the brakes on the motor car will be​

Answer 1

Given :

Mass of the car = 50 kg

Initial velocity = 40 m/s

Final velocity = zero

Time interval = 2 s

To Find :

Force exerted by the brakes on the car.

Solution :

❖ Force is defined as the product of mass and acceleration.

• It is a vector quantity having both magnitude as well as direction.
• SI unit : N

We know that acceleration is equal to ratio of change in velocity to the time interval$.$

Formula of force in term of change in velocity is given by;

• F = m × (v - u) / t

• F denotes force

• m denotes mass

• v denotes final velocity

• u denotes initial velocity

• t denotes time

By substituting the given values;

→ F = 50 × (0 - 40) / 2

→ F = 50 × (-40) / 2

→ F = 50 × (-20)

→ F = -1000 N

Negative sign indicates retardation.

Answer 2

Answer:

1000N

Step-by-step explanation:

Mass is 50kg

Initial velocity is 40m/sec

Time is 2sec

Final velocity is 0 as it is stopped

So acceleration would be v-u/t

0-40/2

=-20m/sec2

F is products of mass and acceleration so force = 50*-20 = -1000 N

Negative sign denotes force exerted is in opposite directions