The velocity (v) - time (t) plot of the motion of a body is shown below :

The acceleration (a) - time(t) graph that best suits this motion is :




Step 1: Analyze the Velocity-Time Graph
Acceleration is represented by the slope of the velocity-time (v-t) graph. The provided graph shows:
Velocity increases linearly over time, indicating constant acceleration.
Step 2: Match with the Acceleration-Time Graph
As acceleration is constant, the acceleration-time (a-t) graph will be a horizontal line.
Step 3: Conclusion
Option (3) correctly depicts the acceleration-time graph. 
A body of mass 1000 kg is moving horizontally with a velocity of 6 m/s. If 200 kg extra mass is added, the final velocity (in m/s) is: