Coefficient of static friction

[hannsparks]

An apple crate with weight of 49N accelerates at 0.5m/s2 along a horizontal a force of 20N apllied above the horizontal at 19 degrees is required to bring the crate on the verge of motion. Find the coefficient of static friction between the crate and the surface.

-usn+20 cos 19 x direction
N+W+20 cos 19 y direction

F=ma F=5x0.5
F=2.5

don't know what to do next..please help

 

[mrjeffy321]

You had an almost identical problem earlier which you figured out,
https://www.physicsforums.com/showthread.php?t=101868
you would work it the same way, but now you have 20 N as the pulling force instead of 14.5.

 

[hannsparks]

I did it exactly the way I did the other problem but according to the book the answer should be 0.445 but I am getting 0.386

 

[hannsparks]

i don't know what I am doing wrong I don't thnik the book is wrong it says 0.445 and I got 0.386 like 4 times in a row

 

[mrjeffy321]

I got .386 too. But that is not to say that I didnt do anything wrong either, but it is a good sign we both got the same answer.

 

[hannsparks]

I redid the question and I got 0.445 I forgot to set fx and fy equal to zero because the crate is not in motion it is on "the verge of motion"