A-Level Mechanics Help

Hi,
I'm a bit stuck on this question and would be great if someone can tell me where to start.
A mass of 5 kg is placed on a rough plane inclined at 25° to the horizontal. A force of 15 N, acting parallel to the plane, can just prevent the mass of 5 kg from sliding down the plane. The force is increased until the mass is on the point of sliding up the plane.
1)Find new value of this force
2)Find the coefficient of friction

First thing is generally to draw a forces diagram with gravity, friction, reaction and the horizontal force on.
Post that once you've tried?

Resolve the forces parallel and perpendicular to the plane but first fix your weight vector it's bonkers

lol ok I'm terrible at drawing diagrams

* Your 5g is a bit off (must be vertical)?
Now resolve along the plane and perpendicular to the plane (or horizontally and vertically)

Resolving Vertically: R- 5gcos25=0
Resolving Horizontally: T-F-5gsin25 (but I don't know what to equate this to?)
*the T is the 'new force'

The system is in equilibrium so the sum of forces must be zero.

Resolving Vertically: R- 5gcos25=0
Resolving Horizontally: T-F-5gsin25 (but I don't know what to equate this to?)
*the T is the 'new force'

ok...so how can you find the new force if there are 2 variables(T and F)

You're told T = 15 N will prevent the mass moving down, so find F.
Then flip its sign to find T so that the mass is almost moving up.

so the new force is 20.7N (3sf)

How?

15=F+5gsin25
F=15-5gsin25=-5.71(3sf)
You said to flip the sign so then I added 5.71 to 15=20.7N

Flip the sign of F in the forces equation as friction is now acting in the opposite direction, then solve for T.

oh ok thanks

Was it correct