Question

Brakes are applied to acar moving with velocity 30m/s.The brakes produced the retardation of 6m/s2. How long will the car take before coming to stop.

Answer 1

Here, initial velocity= 30 m/s
Since the car stops ,so the final velocity= 0 m/ s
Now, retardation = 6 m/s^2
So, by following equation-
v= u + at
Here a will be negative
so, by putting the above values in the equation ,we get-
0 = 30 - 6t
so, 30= 6t
t= 30/6
t= 5 sec.
So, the car will take 5 seconds before coming to rest.

Answer 2

@
u=30m/s²
v=0
a=6m/s²
t=?
________
a=v-u/t
t=v-u/a
t=-30/6
t=-5sec
time =-5sec in acceleration so in retardation it stops in 5sec.
@:-)