A backpack full of books weighing 52.0 N rests on a table in a physics laboratory classroom. A spring with a force constant of 180 N/m is attached to the backpack and pulled horizontally, as indicated in Figure 6-22.
(a) If the spring is pulled until it stretches 2.10 cm and the pack remains at rest, what is the force of friction exerted on the backpack by the table?
(b) Does your answer to part (a) change if the mass of the backpack is doubled

Question

A backpack full of books weighing 52.0 N rests on a table in a physics laboratory classroom. A spring with a force constant of 180 N/m is attached to the backpack and pulled horizontally, as indicated in Figure 6-22.
(a) If the spring is pulled until it stretches 2.10 cm and the pack remains at rest, what is the force of friction exerted on the backpack by the table?
(b) Does your answer to part (a) change if the mass of the backpack is doubled

anonymous · Answer

Which question are you stuck with?

anonymous · Answer

No, the answer will not change as Hooke's law isn't dependent on mass.

anonymous · Answer

Question a

anonymous · Answer

according to Newton's second Law,
|dw:1352977146879:dw|
and since it is not moving, $\Sigma F=0$
$F_f =F_s$ where $F_s =kx$ by hooke's law.
So, $ F_f = kx$, k and x are given.