An object at rest increases its velocity to 10m/s in 3 seconds. What is its acceleration

Acceleration = (change in speed) / (time for the change)

Change in speed = (speed at the end) - (speed at the beginning).

Change in speed = (10 m/s) - (zero) = 10 m/s

Time for the change = 3 sec

Acceleration = (10 m/s) / (3 sec)

Acceleration = (3 and 1/3) m/s² or 3.333 m/s²