Recent content by jonnyboy

can I use sin A = cos(pi/2 - A)?

Homework Statement This one's easy. A 2.9 lb force (P) is applied to a lever. Determine the value of alpha knowing that the moment of P about A is counterclockwise (+) and has a magnitude of 17 lb-in. Homework Equations Moment about a = (Force of x-component)(distance from a to Force...

***I added the attachment with the image; the red arrows show the forces acting on the body. The arrow represents the rope force to the left and has a length of 3 meters and the whole wire is 8 meters long. The rope is parallel to the wire. Both the wire and the rope are on the horizontal sense.

Homework Statement An aerialist is walking a wire of length 8 meters. He is being pulled from the edge with a rope that is 3 m in length. The person weighs 720 N and is in equilibrium. Determine a) the tension of the wire, b) the tension of the ropeHomework Equations Since the person is in...

Homework Statement Two traffic signals are temporarily suspended from a cable as shown. Knowing that the signal at B weighs 300N. Determine the weight at signal C. Homework Equations Red arrows show lengths of cables and their components. Answer is : W_c = 97.7N The Attempt at a Solution I...

Right, thanks. it's the small things that get me. taking the horz component of Q (80sin(35) = P = 45.9) gives the magnitude of p. Then, using law of sines to get alpha, I can get the third angle and then use law of cosines to get mag of R

Homework Statement Two cables are attached to a sign at point A to steady the sign as it is being lowered. Using Trigonometry, determine a) the magnitude and direction of the smallest force P for which the resultant R of the two forces applied at A is vertical, b) the corresponding...

Homework Statement Use a suitable change of variable to find the area of the region R bounded by y=x^2, y=4x^2, y=\sqrt{x}, y=\frac{1}{2}\sqrt{x} 2. The attempt at a solution I am trying to first find the inverse transformations {u & v =?

Got it, so f(r,\theta,z) = r^4 Much simpler!

Homework Statement \int\int_{Q}\int(x^4+2x^2y^2+y^4)dV where Q is the cylindrical solid given by \{(x,y,x)| x^2+y^2 \leq a^2, 0\leqz\leq\frac{1}{\pi}\}Homework Equations When I convert to cylindrical I get f(r,\theta,z) = r^4\cos^2\theta + 2r^4\cos^2\theta\sin^2\theta + r^2\sin^2\theta, but I...

It's going to be hard to think of it visually since we are talking about area of a plane region. So when you have the graph of a function you are talking about the area under the graph from one x to another x. Say, f(x) = 2x from x = 0 to x = 2, then you can see that this is a straight line...

for part b, the rod inertia that I can use is I= (1/12)ml^2, right? Then I can use the parallel axis theorem, I = I_com + md^2

[SOLVED] Undamped oscillations In the diagram below, the disk is mounted vertically on ideal bearings through its center mass. If the system is disturbed from its equilibrium position, determine the frequency of the undamped oscillations. I = 4kg m^2 This one I have no clue about. We rushed...

[SOLVED] Angular momentum and oscillation of disk A large solid disk of mass M and radius R is mounted on a fixed axis through its center using ideal bearings. A small projectile of mass m_1 traveling with velocity v_1 collides tangentially to the slight extension and sticks to the larger disk...

[SOLVED] Ball of putty hits rod (rotation) I need help with three problems. For all of these topics we spent a small amount of class time on. And I'm having trouble knowing where to begin. I have posted each on their own thread. A long thin rod of mass of .2 kg and length .04 m lie flat on a...