3.75m/s²
Acceleration is the rate of change of velocity.
The formula for acceleration is:
acceleration = Δv/Δt
Where Δv is change in velocity and Δt is change in time.
As the initial velocity was 0 and the velocity is now 15m/s, the change in velocity is 15m/s.
The change in time is 4 seconds.
The acceleration is therefore 15/4 so 3.75m/s².
