Answer:
t = 9.05 s
Step-by-step explanation:
Given,
The initial velocity of the car, u = 22 m/s
The final velocity of the car, v = 3.0 m/s
The rate of change of speed of the car is 2.1 m/s,
∴ the acceleration, a = -2.1 m/s²
The acceleration and velocity is given by the relation
a = (v - u)/t m/s²
Therefore,
t = (v-u)/a s
Substituting the values in the above equation
t = (3.0 - 22)/(-2.1)
= 9.05 s
Hence, the time required before the car is traveling at 3.0m/s is t = 9.05 s