Question

A driver of a car traveling at 17.4 m/s applies
the brakes, causing a uniform deceleration of
1.8 m/s2
.
How long does it take the car to accelerate
to a final speed of 13.4 m/s?
Answer in units of s.

Answer 1

vf=vi+a*time
you are given a as -1.8m/s^2, vf=0, vi=17.4m/s solve for time t.

Answer 2

u = 17.4m/s, a = -1.8m/s^2
v = 13.4m/s

Using the first equation of motion:
=> v = u + at
=> (v-u)/a = t
=> -4/-1.8 = t
=> 2.22 seconds

Answer 3

Arora: When you give it away free, it has no value.

Answer 4

Hope you've heard about equations of motion.

For this one we can use v=u+at , where v=final velocity(in m/s) , u=initial velocity(in m/s) , a=uniform acceleration(in m/S^2) and t=time(in seconds).

Now substitute values for the above equation to find the required time.