physics
posted by carlton on .
A 450 g block is at rest on a horizontal surface. The coefficient of static friction between the block and the surface is 0.670, and the coefficient of kinetic friction is 0.380. A force of magnitude P pushes the block forward and downward as shown in the figure below. Assume the force is applied at an angle of 39.0° below the horizontal.
(a) Assuming P is large enough to make the block move, find the acceleration of the block as a function of P. (Use P as necessary and round numbers to the third decimal place.)
a(P) = m/s2
(b) If P = 6.81 N, find the acceleration and the friction force exerted on the block.
a =
Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully. m/s2
Ffriction = N
(c) If P = 13.62 N, find the acceleration and the friction force exerted on the block.
a = m/s2
Friction = N
(d) Describe in words how the acceleration depends on P.

force P is adding to the normal force. Figure that first.
normalforce=mg+Psin39
friction force= mu(mg+Psin39)
Pcos39mu(mg+Psin39)=ma solve for a