Question

The picture below shows a sprinter at 5 positions. He is initially sitting still on a flat track. He starts running when the starting gun goes off. He travels at constant speed for a few seconds, and then he crosses the finish line and comes to a stop again. The following questions will ask you to describe forces and energies at various points along his path.When would the net force on the sprinter be forward?

Answer 1

Answer:

position 2

Explanation:

At position 2, the sprinter started running immediately he heard the sound of the gunshot. This shows that the sprinter accelerated from rest and moved with an increasing acceleration. The magnitude of the final force is higher than the magnitude of the initial force at position 2. Therefore, the difference between the final and initial forces (i.e. net force) is forward (or positive).