Final answer:
To find out how long it takes for a vehicle to accelerate from 30 km/hr to 55 km/hr at 4.3 m/s², convert the speeds to m/s, calculate the change in velocity, and divide by the acceleration. It takes approximately 1.615 seconds.
Step-by-step explanation:
If a vehicle can accelerate at a rate of 4.3 m/s², to find out how long it will take for its speed to change from 30 km/hr to 55 km/hr, we first need to convert the speeds into the same units. We convert 30 km/hr to 8.333 m/s (since 1 km/hr is approximately 0.27778 m/s) and 55 km/hr to 15.278 m/s.
Next, we use the formula for uniform acceleration, which is:
Δv = a • t
where Δv is the change in velocity, a is the acceleration, and t is the time. Here, the change in velocity (Δv) is 15.278 m/s - 8.333 m/s = 6.945 m/s.
Now we can solve for t:
t = Δv / a
t = 6.945 m/s / 4.3 m/s² = 1.615 seconds
So, it takes approximately 1.615 seconds for the vehicle's speed to change from 30 km/hr to 55 km/hr at the given rate of acceleration.