How Do You Solve These Physics Problems Involving Tension, Friction, and Motion?

[bknice02]

1. A 52.0 kg person takes a nap in a (lightweight) backyard hammock. Both ropes supporting the hammock are at an angle of 14.9° above the horizontal. Find the tension in the ropes.

2. 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 155 N/m is attached to the backpack and pulled horizontally. (a) If the spring is pulled until it stretches 1.70 cm and the pack remains at rest, what is the force of friction exerted on the backpack by the table?

3. A box is placed on a conveyor belt that moves with a constant speed of 1.38 m/s. The coefficient of kinetic friction between the box and the belt is 0.920. (a) How long does it take before the box stops sliding relative to the belt? (in seconds) (b) How far has the box moved in this time? (in meters)


I don't expect to be given the answers, I just need to be pointed in the right direction

 

[zwtipp05]

Look at the resultant Forces

F=-kx

not much else I can help you with without you showing what you've done. then we can point out any problems in what you're doing.