Compute the resulting acceleration

[huybinhs]

Homework Statement

A 100 kg trunk loaded with old books is to be slid across a floor by a woman who exerts a force of 500 N down and forward at 30° with the horizontal. If μk = 0.3 and μs = 0.4, compute the resulting acceleration.

Homework Equations

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The Attempt at a Solution

N = mg, of trunk
N = 100kg * 9.8 = 980 N
Push of lady :
N = F sin theta
N = 500N * sin 30 = 250N
Total force being exerted = 980 + 250N = 1230N
friction kinetic force:
f = u*N
f = .3 * 1230N
friction force of moving box = 369N

woman pushes with force:
500N * cos 30 = 433N
So with 433N force of push - 369N friction = 64N of net force on sliding box
Net force = mass * acceleration
64N = 100kg * a
acceleration = 0.64 m/s^2 => INCORRECT => Please help!

 

[dineshnaveen]

we know the formula F=macos theta. and F=mue*mg.from this u can find the force and equal both and find out accelaration