# Search results

1. ### Determine the magnitude and direction of forces

"If A, B, C are pin connected, the system is a truss and members AB and BC are two force members which can only take tension or compression." A professor whom I asked yesterday made everything clear with the above sentence. Thank you SteamKing for all your help. I really appreciate that.
2. ### Determine the magnitude and direction of forces

Which part of my replies gave you, Sir, an impression that I throw up my hands? I am happy to know that. I spent like 10 hrs on this problem before I posted this thread. Anyway, have you solved the problem yourself, Sir? You mentioned "FAx + FCx = 0", and your analysis indicated that FAx and...
3. ### Determine the magnitude and direction of forces

Exactly. By using the first FBD, we have 4 unknowns and 3 equations. Thus, this problem is unsolvable, isn't it? As for the third FBD, which analyzes forces acting on Point B, I believe it is flawed because Fab may not act along line AB, and Fbc may not act along line BC. However, teachers...
4. ### Determine the magnitude and direction of forces

If AB is a rope, well,then I agree that only tension forces can exist thus the direction of force should be along AB.Since the question already mentioned that it is a beam, I suppose the structure can support shear force. Right? If so, why must the force be along AB? What are the subject and...
5. ### Determine the magnitude and direction of forces

Thanks SteamKing. It seems to me that you are saying point B is the system. Am I right? The FBD that you described should look like this: Yes, by using the above FBD, things become rather easy. In fact what you explained was similar to the explanation given by the textbook. You mentioned that...
6. ### Determine the magnitude and direction of forces

Yes, I wasn't given any information about how the frame is fixed to the wall. So I assumed it was fixed support that allows reactive moment. Anyway, I don't understand how we can analyze "the forces acting at a point". Is it true that when we analyze a problem in statics, we must first define...
7. ### Determine the magnitude and direction of forces

I apologize for my mistake. The force diagram should be like this: Thus, we have 6 unknowns and 3 equations. I deem it unsolvable.
8. ### Determine the magnitude and direction of forces

Homework Statement The figure shows a frame with a 100N object hanging on it. Determine the magnitude and direction of forces exerted on AB and BC respectively. Homework Equations ∑Fx=0, ∑Fy=0, ∑M=0 The Attempt at a Solution I believe this question is unsolvable. The free body...
9. ### Tangent problem

This is a typical question in analytic geometry. I believe the textbook must have covered it. There are at least 3 ways to solve it.
10. ### Help finding winning strategies in the following tile game?

I do understand the game from your description (at least 90%). However, I don't quite understand the question you are asking so I am just sharing my view on the game here. Let's say after first turn, the piece is not at the edge of the board, Player 1 will certainly win by issuing an order of...
11. ### Tension in cable and reaction force

Taking a moment with respect to point B should give you more simple equations. If you are doing scalar analysis, you should break your moment into Mx, My, Mz. Use M = r x F instead for vector analysis.
12. ### Work and Potential Energy: To the Moon physics problem

Wow..it must be a hard time for you. Have you learnt about electric field generated by an electric charge? It is analogous to the gravitational field. For example, you will find the equation for electrostatic force ##F=k\frac{Qq}{r^2}## very similar to the equation ##F=G\frac{Mm}{r^2}##. I...
13. ### Introductory Fluid Mechanics book.

Since you are looking for general reading, I recommend Fox and McDonald's Introduction to fluid mechanics by Philip J.Pritchard.
14. ### Banked curve

Thanks ehild for pointing out the keyword "banked" here. Yes, since it is a banked curve, the force involved are those 3 mentioned. In my previous post, I mistakenly mentioned "centrifugal force needed to maintain circular motion", it should be centripetal force.
15. ### Banked curve

Yes, the direction of the frictional force is opposite the other force, but the latter does not points to the centre of the circle. In fact it is a fictitious force, which arises due to the non-inertial frame of the object in circular motion. (Have you wonder why all motorcyclists bend inwards...
16. ### Banked curve

Good. Let's see if we can workout the correct equation. But first you need to have a good idea of all the forces involved. In your scenerio, is there such a force that points to the centre of the circle? What is the direction of the frictional force then?
17. ### Banked curve

Your equation is not correct. I suppose this could be due to your understanding of circular motion. You mentioned sliding force. What is the sliding force? Why is it there?
18. ### Mass-spring system: Steady state solution

Yeah. The answer should have +4/3. Since there is no c in your original equations, you are now solving different set of equations, aren't you? If so, it's natural that you got something that's different from the correct answer, in this case wrong sign.
19. ### Is momentum really conserved in a perfectly inelastic collision?

Yeah, it's my mistake. It should be isolated system, not closed system.
20. ### Mass-spring system: Steady state solution

By equating all the coefficients of sin(3t) terms to -75, cos(3t) terms to 0, 9c to 225, you will be okay. The answer provided is obviously wrong. There should be the minus sign.
21. ### Is momentum really conserved in a perfectly inelastic collision?

Conservation of momentum is the natural result of newton's third law (or 2nd law as some may say). When we apply newton's third law to derive the conservation of momentum, we are essentially looking at two objects acting on each other. Since we are studying only the two objects, they form a...
22. ### Bernoulli's principle in stagnant situations

Your post is interesting. I don't have answer for now, guess I have to investigate a bit. Well, I learnt bernoulli's equation from one of the "every book" you mentioned and I never questioned the use of bernoulli's equation when there is no continuity.
23. ### Ideal fluids, bernouilli's law

##P_{1} = P_{2}## ? How is it possible?
24. ### Angular acceleration of an arm

Maybe there is no need to calculate moment of inertia. Use τ=Fr to calculate τ(net) will do. F can be obtained through F=ma and r can be obtained through finding the centre of mass of the system. Anyways, it is up to the original question raiser to do the math.
25. ### Ideal fluids, bernouilli's law

You are using an equation from fluid statics to analyze a dynamic situation. In dynamic fluid, pressure is never simply density x g x depth. You can study bernoulli's equation and realize that there are static pressure, dynamic pressure and pressure caused by gravity.
26. ### Ideal fluids, bernouilli's law

The explanation is misleading. One should not analyze the situation from this perspective because doing so will cause you to hold F constant, which doesn't make sense.
27. ### Angular acceleration of an arm

Ops! Part B appeared to be more tricky than I initially thought. You can forget using F=ma to solve it. May I know where you get this problem? There are a few assumptions to be made in order to solve this problem. Still, it takes plenty of steps to get the final answer. First, you must...
28. ### Work and Potential Energy: To the Moon physics problem

Your equation is incorrect. Do you know what the meaning of Ue is when you equate it with G*Mem/(rem) ? It is important to understand the physical meaning of every terms in order to write the equation correctly.
29. ### Angular acceleration of an arm

F=ma says that an object with mass m will experience acceleration a under force F. The acceleration you obtained belong to which object? Arm? Ball? Which mass should you use then?
30. ### Angular acceleration of an arm

Now you get it.:smile: