# Search results

1. ### DIRE NEED of HELP on HARDEST Physics Problem Ever

My class didn't get very far. I was disappointed, as I am taking AP Physics C: Mechanics, so I could not really help out as I haven't done E&M at all this year. It was pretty much up to Honors physics students who are currently studying capacitance. Anyway, I have a copy of the solution now...
2. ### DIRE NEED of HELP on HARDEST Physics Problem Ever

Ok, the seniors just gave us the answer. I may be back with another problem later, but I think this it for now. the answer was .46 rad/s
3. ### DIRE NEED of HELP on HARDEST Physics Problem Ever

http://spymaster1027.deviantart.com/art/Physics-84746563
4. ### DIRE NEED of HELP on HARDEST Physics Problem Ever

Ok, so I am in the middle of what is known as the "axe hunt" at my school. It is the culminating event of the year. The seniors puts together a scavenger hunt that is supposed to take 24 hours consisting of various clues that will require juniors to use their athletic and intellectual...
5. ### Spring SHM Problem

1. Homework Statement Two blocks of mass M2 and M1 (M2>M1) are connected by a spring with force constant k and are free to slide on a frictionless table. They are pulled apart and then released from rest. In terms of M1, M2, and k, what would the period of oscillation be? 2. Homework...
6. ### Average acceleration of a ball

I am not sure if you have gotten to impulse, but if you have, then you can solve with those equations. Recall that linear momentum J equals the change in impulse - J=mv2-mv1 Also remember that J=Favg*T You'll have solved for J, and you already know that T=3 ms, so you should be able to find...
7. ### A Few Questions About SHM

I have been doing problems for the last two hours, and still haven't really gotten much further on figuring this out..
8. ### A Few Questions About SHM

I have been doing quite a few SHM problems, and I just have a few questions in general. A lot of questions evolved from one particular problem type: A mass attached to the end of a vertical spring of spring constant k. My questions: 1. How can we prove that we can use the equation...
9. ### Proof of w=(k/m)^(1/2)

So I am attempting to prove the simple harmonic motion equations with calculus so as to develop a better understanding of shm problems and have more flexibility when it comes to solving them. I am having a bit of trouble understanding the proof of w=(k/m)^(1/2) Here is how I am doing it. I...
10. ### Direction of Rolling/Sliding Friction

This much more of a general question that I've encountered in quite a few problems and I haven't found an answer to in my books or searching the net yet. Take, for example, a ball that has been propelled into motion by a spring gun on the floor. Initially, the ball accelerates so that the ball...
11. ### Graph of Kinetic Energy v. Displacement of a Falling Object

ahh.. v^2=v0^2+2a(x-x0) but since initial velocity in the y direction is 0 v^2=-2g(x-x0) and since -2g is a constant, v^2 is directly proportional to displacement, and thus kinetic energy is directly proportional to displacement! Thanks Doc Al!
12. ### Graph of Kinetic Energy v. Displacement of a Falling Object

[solved] Graph of Kinetic Energy v. Displacement of a Falling Object 1. Homework Statement Draw and label a graph with energy for the y axis and displacement for the x axis of the kinetic energy and potential energy of an object in free-fall that started with a horizontal speed of 30 m/s from...

14. ### Gravitational potential energy

[SOLVED] Gravitational potential energy edit: solved
15. ### Direction of angular acceleration

Actually, I think I get it now after messing around with some pictures..still, I think this was a stupid and poorly phrased problem.
16. ### Direction of angular acceleration

1. Homework Statement Imagine a car driving on the XY plane in the +y-direction. If it is slowing down, in what direction is the angular acceleration of the wheels? (a) the +x-direction (b) the -x-direction (c) the +y-direction (d) the -y-direction (e) the +z-direction 2. Homework Equations...
17. ### Moment of inertia of a merry-go-round

ahhh, yeah, see it said a merry-go-round at a playground so I was thinking of that thing where there are just bars extending from the center and you have to hold on as it spins really fast. I don't know what it is called but I thinked that they stopped making them for safety reasons. Those...
18. ### Moment of inertia of a merry-go-round

In a certain problem I was working on, it asks for the inertia of a merry-go-round, and my first instinct was that it would be the inertia of a disk about its central axis I=(1/2)MR^2, but the solution actually uses I = MR^2 the rotational inertia of a hoop about the central axis. Why do they...
19. ### Studying Trouble Studying at Home?

deleting facebook account?!?! gahh..I wish I had the nerve to do that, but it would probably save like a few hours for other things each week of my life
20. ### Linear momentum bullet problem

so when I get v0/6 for part A, that is precisely what they want..if so, awesome :) then the last two parts are fairly simple
21. ### Linear momentum bullet problem

yeah, part c was for the block :) ahh..I thought I had the right answer originally but it didn't say if variables were supposed to be left in the problem, so I kind of doubted myself. Thanks for the help you guys. I am learng physixguru, maybe slowly, but learning. lol
22. ### Physical pendulum oscillation

ah! that helps a lot. Thank you so much. When I changed it to (1/12)mL^2 and used d instead it worked out great. I was forgetting about where it was rotating. Once again, thanks so much!
23. ### Physical pendulum oscillation

I just spent another 30 minutes working on the problem...and no luck :(
24. ### Physical pendulum oscillation

1. Homework Statement A physical pendulum consists of a meter stick that is pivoted at a small hole drilled through the stick a distance d from the 50 cm mark. The period of oscillation is 2.5 s. Find d 2. Homework Equations T=2PI*sqrt(I/mgh) I(com)=(1/2)mL^2 parallel axis theorem...

1. Homework Statement A girl of mass M stands on the rim of a frictionless merry-go-round of radius R and rotational inertia I that is not moving. She throws a rock of mass m horizontally in a direction that is tangent to the outer edge of the merry-go-round. The speed of the rock, relative...
26. ### Moment of inertia cylinder problem

1. Homework Statement A bucket of water of mass 20 kg is suspended by a rope wrapped around a windlass in the form of a solid cylinder 0.2 m in diameter, also of mass 20 kg. The cylinder is pivoted on a frictionless axle through its center. The bucket is released from rest at the top of a...
27. ### Equilibrium problem involving wierd static friction

This is not necessarily a homework problem, but a sample problem of my book that I do not quite understand. A rock climber with mass m = 55 kg rests during a "chimney climb," pressing only with her shoulders and feet against the walls of a fissure of width w = 1.0 m. Her center of mass is a...
28. ### Equilibrium Ball attached to wall problem

oh, thanks!...so t*cosx-mg t*cosx=mg replace L/a for cosx t*(L/a)=mg t=mg/L*a by pyth. theorem a = sqrt(r^2+L^2) t=(mg/L)sqrt(r^2+L^2) THANK YOU SO MUCH! It feels so good to get that problem done. For awhile I thought that there would be something way complex to do that would take...
29. ### Equilibrium Ball attached to wall problem

1. Homework Statement A uniform sphere of mass m and radius r is held in place by a massless rope attached to a frictionless wall a distance L above the center of the sphere. Find (a) the tension in the rope and (b) the force on the sphere from the wall. 2. Homework Equations net...
30. ### Completely Inelastic Collision: A block and a block with a spring

re-tried it a few more times to no avail