A car is coasting backwards downhill at a speed of 2.6 m/s when the driver gets the engine started. After 2.5 s, the car is moving uphill at 4.6 m/s. Assuming that the uphill is the positive direction, what is the car's average acceleration?

a=changeV/time=(4.6-(-2.6))/2.5=you do it.

To find the car's average acceleration, we can use the formula:

Average acceleration = (Change in velocity) / (Change in time)

First, let's find the change in velocity. The car starts at a speed of 2.6 m/s when coasting backwards, and after 2.5 seconds, it is moving uphill at 4.6 m/s.

Change in velocity (Δv) = final velocity - initial velocity
= 4.6 m/s - (-2.6 m/s)
= 4.6 m/s + 2.6 m/s
= 7.2 m/s

Next, let's find the change in time. The time taken is given as 2.5 seconds.

Change in time (Δt) = 2.5 s

Now, we can substitute these values into the formula:

Average acceleration = Δv / Δt
= 7.2 m/s / 2.5 s
≈ 2.88 m/s²

Therefore, the car's average acceleration is approximately 2.88 m/s².