Answer:
The acceleration of the object is 20 meters per second square = 20 m/s^2
Explanation:
Recall that acceleration is defined as the change in velocity divided the time it takes for the change. Therefore , if the object accelerates from rest (zero velocity) to 70 m/s , the change in velocity is (70 m/s - 0 m/s = 70 m/s)
which divided by the 3.5 seconds it took for the change, gives:
acceleration = (70 m/s / 3.5 s ) = 20 m/s^2
