Question

If a car is moving with a speed of 18 km/h suddenly brakes are applied in order to stop the car just before hitting a dog at distance of 300 m. how long will the car take to stop?​

Answer 1

Explanation:

(v)^²-(u)^²=2as

o-(5/18×18)^²=2as

25=2×a×300

a=300/25

a=1/24ms^²

2.a=v-u/t

1/24=0-5/t

t=1/24×5

=120s

120/60

2 minutes.

ANSWER.

Answer 2

Answer:

Given, Speed=18km/h,t=5s

a)The speed of the car in m/s=18×

18

5

=5 m/s

b) The retardation is:

a=

t

v−u

=

5

0−5

=1m/s

2

c) The velocity of the as a funcition of time 2sis:

v(t)=5−t⇒v(t)=5−2=3m/s=10.8 km/h