General

[quote=gragon]A 5.0 kg object is at rest on a horizontal surface. The coefficient of static friction between the object and the surface is 0.50µs and the coefficient of kinetic friction is 0.40µk. A person pushes to the left on an object with a gradually increasing horizontal applied force. Describe what will happen to the acceleration and net force as the horizontal applied force increases by identifying both the direction and magnitude. (Explain your reasoning)

A 10kg mass is held against a wall with a force of 220N.
a) Find the minimum coefficient of the static friction. (I found this out already. It is 0.45µs.)
b) Find two ways of making the mass accelerate at 2.0m/s^2 [Down] if the coefficient of kinetic friction is 0.30µk.

A 20.0m long rope is tied to a beam on a ceiling. The rope can only safely hold a mass of 120kg. What is the least amount of time it would take an 85kg person to climb the rope without breaking it?

well, for the first one, you firstly need to find how much force is required to overpower the force of static friction.
Ff = force of friction
Fn = normal force

Ff = µFn
Ff = 0.50kgx9.8m/s^2 x 0.5
Ff = 2.45N

therefore, a person must push with a force of 2.45N to start the object moving
Now we need to find out what the acceleration of the object is at this force
Fa = force applied = 2.45N
Fnet= Fa - Ff
Fnet = 2.45N - 0.5kg x 9.8m/s^2 x 0.4
Fnet = 2.45N - 1.96N
Fnet = 0.49N
mass x acceleration = 0.49N
so 0.50kg x a = 0.49N
a = 0.98M/s^2

So once the object starts moving, it will accelerate at 0.98m/s

still working on the rest[/quote]

Ahh That's a lot of work there I really appreciate this ^^ Thanks xDD

[quote=Affair]oh goddamn it I just took physics last year and I can't remember this crap.

good luck, though ;~;
...i'm going to go look over last year's notes now...[/quote]

Thanks a lot ^^ Me and my friends found out how to do the last question I posted up there..

[quote=itDontMAtter]Note to self: Don't take physics.[/quote]

Ehh, it's MUCH more interesting than chemistry >< People think Physics is all math.. They thought wrong..

Note to self: Don't take physics.

Yeahh.. I'm gonna have problems with this :x

Yeah, no help at all T.T