Answer: To determine the change in speed of a car that accelerates at a rate of 4.5 m/s² for 4 seconds, we can use the following formula:
Δv = a * t
where:
Δv = change in speed
a = acceleration
t = time
Substituting the given values, we get:
Δv = 4.5 m/s² * 4 s
Δv = 18 m/s
Therefore, the change in speed for the car is 18 m/s.