consider the free body diagram. if the sum of the tension forces is equal to the force of gravity, which description best applies?
a) a book is at rest on a tabletop.
b) a physics student rests a backpack upon one shoulder.
c) a girl hangs by both hands, motionless, from a trapeze.
d) a girl falls slowly to earth while strapped to a parachute.

C)A girl hangs by both hands, motionless, from a trapeze.

Explanation:

The free body diagram in the figure gives us several pieces of information:

- There are two forces upward and one force downward. --> these could correspond to the forces of the two harms of the girl (upward) and the weight of the girl (downward)

- The sum of the tension forcs is equal to the force gravity --> this tells us that the net force is zero, therefore this could corresponds to the girl hanging motionless from the trapeze.

Let's see why the other options are not acceptable:

A)A book is at rest on a tabletop.   --> In this case we would only one have one force downward (the force of gravity) and one force upward (the normal reaction of the tabletop)

B)A physics student rests a backpack upon one shoulder.  --> this does not corresponds to two forces upward and one force downward

D)A girl falls slowly to Earth while strapped to a parachute. --> Again, in this case we would have one force downward (force of gravity) and one force upward (the air resistance on the parachute)

So, the only possible option is C.

d) none of the above ( it is an axial load that is the answer).

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