Recent content by emzee1

Figured it out, block A has 1/2 the acceleration of point P

Thank you so very much! Cleared up a lot of confusion for me!

So the acceleration of block A would be 3 m/s^2 ? Putting this into the equation: 2T-mg=ma; where m=50kg and a = 3m/s^2, solving for T gets me 320 N. P_input = 320(12), and solving for P_ouput; ((320(12)/.8)=4800W. Did I do everything correctly? Because the answer given is 4,803.75W...

I'm really bad with multiple pulley-systems. Because there are 2 pulleys, is the acceleration just for block A just 1/2 of that at point P?

That is incorrect unfortunately. I've tried that also. The answer given is that the Power input should be 4803.75 W. Solving your way does not give that answer (.8 = Power_input/Power_output).

So, after reviewing my notes. Block A isn't moving as fast/at the same rate as point P. How do I exactly solve for the acceleration for block A? Seeing I have these two equations then: 2T - mg = ma; where I don't know T or a (acceleration) of the block At point P, the only two forces I can...

Well, reviewing some previous examples, it doesn't. How do I go about solving for the acceleration for block A, and does it matter for the overall problem? Because I can't solve the following equation: 2T-mg = ma; as I do not know T nor a and I'm not entirely positive about the free-body...

I'm not sure about the last point you made. Is the weight being pulled as fast and at the same rate as point P?

Homework Statement At the instant shown, point P on the cable has a velocity 12 m/s, which is increasing at the rate of 6m/s^2. Determine the power input of motor M at this instant if it operates with an efficiency of 0.8. The mass of the block A is 50kg. I've attached a picture of the...

Homework Statement At the instant shown, point P on the cable has a velocity 12 m/s, which is increasing at the rate of 6m/s^2. Determine the power input of motor M at this instant if it operates with an efficiency of 0.8. The mass of the block A is 50kg. I've attached a picture of the...

a and b be anything and c be greater than zero?

So the exact opposite of what I just said?

My main reasoning behind that was since it's a dot product between F and <0,0,1>, technically a and b can be anything, but doesn't c have to be less than 0 to make the integrand negative?

So, basically, at the end am I just looking at the dot product of F and the vector [0,0,1]? If that is the case from what I've read in the posts above, wouldn't just the z-component (which is C) have to be less than zero, while the others are just less than or equal to zero?

Homework Statement I know I posted a question yesterday also, but this homework is getting on my nerves. My prof isn't the best out there. So basically the question is as follows: http://img812.imageshack.us/img812/8130/problem6.png Homework Equations Not sure, I sort of answered the...