Thank you! If I use the vector method I become indeed a positive number. This method can always be used? Also If I am working not with vectors as in my picture above?
And if I work with scalars, your method is just to remove the sign? Or maybe if ag is pointing to the positive direction and the...
Homework Statement
Counter clockwise is positive, right is positive and up is positive.
My problem statement: When I use the formula ag = alfa*r do I have to take signs into account? Or is this formula just for the magnitude and will the signs be already taken into account in other equations...
Thanks guys. Yes indeed, the detail of the fixed lever did not get my attention. Thats why I was confused.
Another question loose from this excercise.
What with the acceleration? Image you have a wheel, the instantaneous center of rotation is at the ground. This wheel also has an acceleration...
Hi,
What do you mean with "Q"? I already calculated all the velocities and angular speeds. I had to know all the instantaneous centers of velocity for this. I am really confused about this. I think the two instantaneous centers are at the center points of the gears (this is what my intuition...
Are you sure? For example on the picture underneath, the red point was de center of velocity for the red gear (small and big are one solid gear).
I am a little bit confused. How can i find the velocity center. It is not because a disk is fixed because of a axis that the axis is the...
That is indeed not the full problem statement. But my problem statement is which are the instantaneous centers of velocity?
There is a fixed axis through O. If you need the angular speeds they are:
wz = 5 rad/s (given)
wa = 15 rad/s
wR = 3 rad/s
Everything else is in the picture.
Thanks
Homework Statement
Where are the instantaneous centers of rotation?
Instantaneous center of rotation =
1. Velocity is 0 in this point.
2. This can be also a point where 2 parts "touch" each other and have the same velocity in this point.
Homework Equations
/
The Attempt at a Solution...
Just derivate of the term above. Chain rule for derivates...?
EDIT: Okay, this is my fault. The second term doesn't need to be there.
I was confused because of the image above. I think that the derivate of above is dr/dt and that's why Theta has to be also be derived. (chain rule?). In this...
Sorry guys, I didn't want to be inpolite. This is the translation:
The cylinder C can only move in the slot. The movement is described by r = 0,6*cos(theta) m. The lever OA turns left (counter clockwise) with an angular speed of 2 rad/s and has a angular acceleration of 0,8 rad/s^2 at the...
Yes indeed, I know that the acceleration sign is - or + if a result is negatif, it is poiting in the other direction. But in this case, my ar was positive. How did I know that the right part of the equation to calculate the angular speed must be positive and NOT negative? This is not the...
Thank you. But how do I know this? Is 'r' a vector? I see the formulas just as a formula where I have to fill in my value of something without changing signs in the formula. How do I know when I can change a value? Maybe this is a weird question, but I want to get the bigger view. Thank you
Homework Statement
Calculate the force on the cilinder. You need the angle of the tangent and r.
Homework Equations
Down under here. The solution for the angle is 30°. But why does the formula I used did not work out?
My solution is 40,9°, why isn't this correct for this excercise?
The...
http://blob:http%3A//imgur.com/fe849a41-c1e6-4557-98ab-d2fc40a81c18
I have to put my acceleration, calculated out of the free body diagram, in the ar = ... equation. Since my ar is positive and r(double point) = 0, I can't take the root to find my angular acceleration. If something is not...
Sorry thought the question was in the picture.
The question is, calculate the angular speed so that r = 0,72 m. Everything else that you need is in the picture.
The spring is 0,4 m long in rest. Spring constant is in the picture.
Thanks guys!