What will be the horizontal acceleration

[JaZZyCooL]

Homework Statement

a 4.00-kg block is sliding up the plane on a 30 degree incline. If the coefficient of kinetic friction between the block and the inline is .700. What will be the acceleration of the block if a 50-N horizontal force pushes on the block?

Homework Equations

50 - mgsin(30) - Uk*mg*cos(30) = ma

The Attempt at a Solution

[/B]
I am getting answer 6.65 something whereas the correct answer is 4.40 m/s.
I suck at this topic. This is the weakest point I would appreciate your help.

 

[berkeman]

Homework Statement

a 4.00-kg block is sliding up the plane on a 30 degree incline. If the coefficient of kinetic friction between the block and the inline is .700. What will be the acceleration of the block if a 50-N horizontal force pushes on the block?

Homework Equations

50 - mgsin(30) - Uk*mg*cos(30) = ma

The Attempt at a Solution

[/B]
I am getting answer 6.65 something whereas the correct answer is 4.40 m/s.
I suck at this topic. This is the weakest point I would appreciate your help.

It seems like your setup is close. can you post all of your work so we can check it?

 

[JaZZyCooL]

It seems like your setup is close. can you post all of your work so we can check it?

50 - 4.0*9.8*sin(30)-4.0*0.7*9.8*cos(30) = 50 - 23.76 = 26.64
26.64/4.00 = 6.56 m/s^2

 

[TSny]

50 - mgsin(30) - Uk*mg*cos(30) = ma

Looks like you've worked the problem for the case where the 50 N force acts parallel to the incline. But the force is acting horizontally.

 

[JaZZyCooL]

So what will be the equation if the force is acting horizontal?

 

[TSny]

When you dealt with the weight mg, you broke it into components parallel and perpendicular to the slope. Do the same for the 50 N force.