Question

A FORCE OF 50 N ACTS ON A MASS OF 10 KG AT REST WHAT IS ITS ACCELERATION WHAT IS ITS VELOCITY AFTER 2 SECONDS IF THE SAME FORCE ACTS

Answer 1

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Method 1 (mass is irrelevant):

50N acting for 10s is an impulse of 500Ns, giving the object a momentum of 500kgm/s.

To lose this much momentum and return to stationary requires an opposing impulse of 500Ns.

To occur in 5s this requires a force of 100N.

Method 2:

F=ma gives an initial acceleration of 25m/s2.

The SUVAT expression v=u+at gives a speed of 250m/s.

In order to stop in 5s, v=u+at shows an acceleration of 50m/s2 is required.

F=ma gives a required force of 100N.