Recent content by nab_

ahh okay. I think I understand that

I don't know. can ##P_1=0## even if the plane is not completely horizontal ( ##\theta=0##)

OH I GOT IT! so I managed to simplify both ##P_1## and ##P_2## after factoring out ##\cos\theta## ##P_2= \frac{\tan\alpha+\tan\theta}{1-\tan\theta\tan\alpha}=\tan(\theta+\alpha)## ##P_1=\frac{\tan\theta-\tan\alpha}{\tan\theta\tan\alpha+1}=\tan(\theta-\alpha)## which by the sum and difference...

##P_2 =\frac{\tan\alpha W\cos\theta + W\sin\theta}{\cos\theta-\tan\alpha\sin\theta}## what do you mean by ratio

So I got these two equations for P2 ##W \sin \theta +F - P \cos \theta = 0## ##R=P \sin \theta +W \cos \theta## together: ##W \sin \theta + \tan \alpha (P \sin \theta + W \cos \theta ) - P \cos \theta =0## and then rearranged; ##P = \frac{-\tan\alpha W\cos \theta -W\sin \theta...

I still wasn’t really able to get the right answer. I don’t know where I’m going wrong but I keep hitting a dead end. thank you so much for your help :)

sorry I had the signs muddled and also wrote tan (theta) instead of alpha. so I rewrote the equation to get ##Wsin \theta -tan \alpha Wcos \theta -tan \alpha Psin \theta -Pcos \theta## =0 And then rearrange for P: P= ## \frac {Wsin \theta -tan \alpha Wcos \theta }{tan \alpha sin \theta +cos...

is this right so far

Oh ok so because P is acting horizontally into the plane the normal reaction force would increase. So also add in -Psin θ when calculating for the resultant forces perpendicular to the plane?

Equal to P1 ?

I don’t understand what would happen to the normal force as it goes from P1 to P2. I thought the only thing that would change is the direction of friction. It is hard. I didn’t come across any similar problems in practice questions but I think we have covered all the necessary stuff to apply...

does that look right

The best I could do was draw a forces diagram. I know that friction would be working up when the block is on the point of slipping down the plane and friction will be acting down the slope against the direction of motion when the block is on the point of slipping up the slope. (not even sure if...