Question

If the net force acting on a body is zero, then will the body remain necessarily in rest position?

Answer 1

We are asked to find the displacement for a given duration with just a graph for the motion given. All we have to know is that the area under the speed time graph gives the distance covered. For the second part, find where the graph becomes parallel to the time axis as this would imply constant speed which further implies uniform motion.

Complete step-by-step solution:
In the question, we are asked if a body necessarily maintains its rest position if the net force acting on this body is zero. No, the body shouldn’t necessarily be at its rest position when the net force on this body is zero.
You may recall the first law of motion which states that every body maintains its state of rest or of uniform motion, until and unless an external force acts on it. So, a body executing uniform motion could maintain its motion without any force acting on it.
The net force on a body is zero just imply that the body would no longer accelerate but would maintain its state of rest or of uniform motion. This could be explained by the second law of motion which is mathematically given by,
$F=ma$

Note: However, the body could be at rest when the net force on it is zero but this is not a necessary condition. This body would only start moving on application of an external force. Similarly for a body executing uniform motion would only change its speed on being acted upon by an external force.