Question

An object is moving up an inclined plan. It's velocity changes from 15m/s to 10m/s in two seconds. What is its acceleration ?

Answer 1

Here, the velocity decreases with time,
Hence it is Negative Acceleration or Retardation.
Initial Velocity(u) = 15m/s
Final Velocity(v) = 10m/s
Time taken(t) = 2sec
Acceleration = Rate of change of velocity
                     = Change in Velocity/time
                      = v-u/t
                      = 10-15/2                   
                      = -5/2
                     = -2.5
Therefore, Negative acceleration= -2.5m/s*s
Or, Retardation= 2.5m/s*s