Can anybody help with physics?

1. Break the force into components

you want part of the pulling force in the x direction and part in the y direction

2. Find the weight of the box

This force will be entirely in the negative y direction

3. Sum the forces in the Y direction

You should have the weight going down, but also a component of the pulling force going up. The resultant normal force that the floor exerts on the box will be equal to (weight box-y component of the pull). This normal force is what you will be using to find the frictional force

4. Find the frictional force

Friction is equal to the normal force that the floor exerts on the box (what you found last step) multiplied by the coefficient of friction. Frictional forces ALWAYS oppose motion, so in this case, in the opposite direction of the pull.

5. Sum the forces in the x direction

You should still have the x component of the pulling force left. Sum it with the frictional force (remember, the friction counteracts the pulling so really you're subtracting the frictional force from the pulling force). This will give you the net force in the x direction.

6. Find the acceleration

You should know that F = ma or the net force is equal to the mass times the acceleration. Take your net force that you found in step 5, and set it equal to your mass (35kg) times the acceleration, a. Now, solve for a.

And you're done! I can't solve it for you, as there are details critical to the problem that you left out, sorry

The net force f = MA = P - F in vectors. As all the motion is along the X direction, we have fx = MAx = Px - Fx along the surface.

So Ax = (Px - Fx)/M = (P cos(theta) - k (W - P sin(theta)))/M = (185*cos(radians(25)) - .45*(35*9.8 - 185*sin(radians(25))))/35 = 1.38571174 = 1.39 m/s^2. ANS.

Note Py = P sin(theta) is the amount of lift caused by the pull P at angle theta. W - Py = N the normal force from which Fx = kN friction force is derived.