Question

What is the average braking force of a 1000-kg car moving at 10 m/s braking to a stop in 5 s?

Answer 1

The average braking force is `=2kN`

Explanation:

The mass of the car is `m=1000kg`

The initial velocity of the car is `u=10ms^-1`

The time is `t=5s`

The final velocity of the car is `v=0ms^-1`

Apply the equation of motion,

`v=u+at`

To calculate the acceleration,

`a=(v-u)/t=(0-10)/5=-2ms^-2`

Then,

Apply Newton's Second Law of Motion to calculate the braking force,

`||F||=m||a||=1000*2=2000N`