Which force best represents Fg?

A weight lifter is pushing a barbell upward with a force of 90 N.
The weight of a barbell acting on a weight lifter is 80 N.
The amount of upward force of a table on a box is 25 N.
A box on a rough table has difficulty sliding past 25 N of force.

In the circuit, the switch s has been open for a long time and r = 125 kohm. it is then suddenly closed. (a) determine the time constant before the switch is closed. s (b) determine the time constant after the switch is closed. _ s (c) let the switch be closed at t = 0. find the current in the switch as a function of time. (use t for time. express your answer in milliamps and seconds.) i(t) =_