Question

a car of mass 1000kg is moving with a velocity of 30m/s on a horizontal straight road. on seeing red light of the traffic signal, the driver Applies brakes to produce a constant braking force of 4 kN (1) find the deacceleration of the car (2) what time will the car take to stop (3) how much distance would it travel during this motion

Answer 1

here is your answer

given :

mass = 1000 kg

initial velocity (u) = 30 m/s

final velocity (v) = 0

force (f) = 4 kN = 4000 Newton

to find : deacceleration of the car, time taken to stop the car & distance travelleld

solution :

1. deacceleration of the car

force = mass×acceleration

4000 = 1000×a

a = 4 m/s^2

so, car will deaccelerate at -4 m/s^2

2. time taken by the car to stop

by using 1st equstion of motion

v = u+at

0 = 30+(-4t)

t = 7.5 seconds

so, time taken by the car to stop will be 7.5 seconds.

3. distance travelled

by using 3rd equation of motion

v^2 = u^2+2as

0 = (30)^2+2×(-4)×s

8s = 900

s = 112.5 meter

distance = 112.5 meter

so, the distance travelled by the car is 112.5 meter.