Conceptual Dynamics - Independent Learning

Friction - Conceptual Example 5.4-3

A woman exerts a constant horizontal force (F) on a large box. As a result, the box moves across a horizontal floor at a constant speed v_o.

The constant horizontal force applied by the woman:

has the same magnitude as the weight of the box.
is greater than the weight of the box.
has the same magnitude as the total friction force which resists the motion of the box.
is greater than the total friction force which resists the motion of the box.

If the woman in the previous question doubles the constant horizontal force that she exerts, the box then moves:

with a constant speed of 2v_o.
with a constant speed that is greater than v_o.
for a while with an increasing speed, then with a constant speed thereafter.
with a continuously increasing speed, assuming it is a super woman and is physically able to run with an infinite speed.

If the woman suddenly stops applying a horizontal force to the box, then the box will:

immediately come to a stop.
continue moving at a constant speed for a while and then slows to a stop.
continue moving at a constant speed.
slow continuously to an eventual stop.
increase its speed for a while and then start slowing to a stop.

The above questions are theoretical and idealized, what would happen in the real world?

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