What am i doing wrong? :/ (1 Viewer)

[mreditor16]

I can't believe I'm getting this wrong. But what am I doing wrong?

this is the provided solution for resolving the forces of the past hsc Q (2011):



here is my working out:



lol I never have a problem with resolving forces, but I am getting opposite to the answer. :/

Thanks

 

[xc1408]

Hi there, where you have theta (for your normal component) should be 90-theta because its vertically opposite the angle in the lower triangle on the sphere. Not quite sure if this answers your question.

 

[mreditor16]

Hi there, where you have theta (for your normal component) should be 90-theta because its vertically opposite the angle in the lower triangle on the sphere. Not quite sure if this answers your question.

hmm that works

but I'm just confused about where I went wrong myself :/

did I assume something incorrectly lol?

 

[xc1408]

I also believe you have probably assumed that the normal force is 90 degrees to the plane, which is incorrect.

 

[faisalabdul16]

I'm not sureeee what you've done, but all you had to do was alternate angles for the theta in the bottom of the triangle and then vert opposite angles

 

[mreditor16]

I also believe you have probably assumed that the normal force is 90 degrees to the plane, which is incorrect.

okay makes sense. thanks

 

[mreditor16]

I'm not sureeee what you've done, but all you had to do was alternate angles for the theta in the bottom of the triangle and then vert opposite angles

yeh I know :/

 

[IR]

you are incorrectly assuming that the string is tangential to the sphere?

 

[xc1408]

you are incorrectly assuming that the string is tangential to the sphere?

Yep which is why the normal force can't be assumed 90 degrees to that string

 

[IR]

Yep which is why the normal force can't be assumed 90 degrees to that string

A rare visit xncn. I see a state rank from you srs.

 

[mreditor16]

you are incorrectly assuming that the string is tangential to the sphere?

hmm okay

thanks guys

 

[xc1408]

A rare visit xncn. I see a state rank from you srs.

sarcasm so strong

 

[IR]

sarcasm so strong

I knew that was coming. That's why I clearly said 'srs' which meant it wasn't sarcasm. You have great talents and literally an all rounder and very helpful ofc to others.