Answer: So, the time it takes for the speed of the car to change from 0 m/s to 28 m/s at its maximum acceleration, is 1.4 seconds.
Step-by-step explanation:
It is an exercise in rectilinear uniformly varied motion (MRUV).
As it is asking us to calculate the time, we apply the following formula:
t = (Vf - Vo)/a
Where
- t = time
- Vf = Final speed
- Vo = Initial velocity
- a = acceleration
It tells us that the car has a maximum acceleration of 20 m/s^2, with speeds from 0 m/s to 28 m/s.
Since the car starts from rest, it has an initial velocity of zero.
We clear the formula t = (Vf - Vo)/t , of the initial velocity and we are left:
t = Vf/a
Where
- t = time
- Vf = Final speed
- a = acceleration
We substitute and solve:
t = (28 m/s)/(20 m/s²)
t = 1.4 seseconds
So, the time it takes for the speed of the car to change from 0 m/s to 28 m/s at its maximum acceleration, is 1.4 seconds.