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1. ### Maximize Range of Projectile Launched from Cliff

Okay I have derived both equations. dR/dx = v*(cos(x)t' - sin(x)t) dH/dx = v*(cos(x)t + sin(x)t') - gt*t' I am unsure where to take these results. Can you help me?
2. ### Maximize Range of Projectile Launched from Cliff

I'm not that familiar with this strategy of differentiation. But I thank you for giving me this new technique to me. I definitely have to try this out, and hopefully master it.
3. ### Maximize Range of Projectile Launched from Cliff

This is an amazing solution. Thanks for taking the time to write this. The source you linked also looked fantastic. Thanks!
4. ### Maximize Range of Projectile Launched from Cliff

Like R = vcos(x)t and H = vsin(x)t - 1/2gt^2?
5. ### Maximize Range of Projectile Launched from Cliff

Thanks for your replies. I did that. But I got the same displacement equation that I posted. t = (vsin(x)+sqrt(v^2*sin^2(x)+2gh))/g. I got this for the time period.
6. ### Maximize Range of Projectile Launched from Cliff

I came up with this problem and did the work, that is hardly an example of low-effort. I don't think I understand the hint well. Do you happen to know the solution?
7. ### Maximize Range of Projectile Launched from Cliff

Can you show me how you would do this problem? You seem like you know what's up.
8. ### Maximize Range of Projectile Launched from Cliff

Sorry about the messy equations. When I took the derivative of range vs angle, I got a very complicated output. Therefore I thought it was difficult to optimize using that solution to find an expression for the angle. That's why I thought there may be a different or better approach available.
9. ### Maximize Range of Projectile Launched from Cliff

I found the function of the range of the projectile launched from a cliff. R = vcos(x)((vsin(x))+sqrt(v^2sin^2(x)+2gh))/g I stopped here because I feel like taking the derivative and optimizing for maximum would spiral out of control. Is there another approach to this problem?
10. ### Kinematics Problems

Hahahaha, I was sitting there wringing my brain out figuring out what I did wrong. Now I see. Thank you!
11. ### Kinematics Problems

For this problem I tried to find when the binoculars reaches the maximum height. So, (0.75 + 1.28)/2 = 1.015s. Using that information I can solve for the initial velocity. v_o = gt = 9.947 m/s. Then using the initial velocity I can solve for the height of John using the 2nd kinematics equation...
12. ### B What are the general calculus concepts used in classical physics?

Thanks, that's what I was looking for.

Question.
14. ### Solving a Trigonometric Equation: v^2*sin(180-2theta2)/g

Yeah. I got it with the trig identities.
15. ### Solving a Trigonometric Equation: v^2*sin(180-2theta2)/g

Ohh... ok. So it has something to do with the sum and difference identities. Thank you.
16. ### Solving a Trigonometric Equation: v^2*sin(180-2theta2)/g

theta1 = 90- theta2 I substituted that into v^2*sin(2theta1)/g So I get v^2*sin(180-2theta2)/g Now I'm stuck. What do I do next?
17. ### Instantaneous versus average velocity?

I have a hard time understanding what this problem even means. So I can't even begin with it.
18. ### B What exactly is Dimensional Analysis?

Thank you Greg!
19. ### B What exactly is Dimensional Analysis?

Can someone explain it to me exactly how dimensional analysis works (perhaps gives some examples.) What use does it have? Is it a convenient way to check your solutions? My teacher showed this example E ~ G, M, R [E] = k[G^α * M^β *R^γ] Maybe someone can explain this.
20. ### B Feynman Diagrams and QED

So sorry that I'm bombarding you with questions. I may be repeating myself here. Coming back to the basic scenario of two electrons shot at each other and bounce off. That is what the most basic Feynman diagram represents I think. In classical physics, the electrons are surrounded by an...
21. ### B Feynman Diagrams and QED

So how did Feynman arrive at "electron emits a virtual photon?" And it carries momentum which causes electrons to recoil and deflect off each other.
22. ### B Feynman Diagrams and QED

Ok, I accept that they just do it. But do electrons just go off an emit photons randomly? Or only when a circumstance happens? Is there a pattern to it?
23. ### B Feynman Diagrams and QED

What's the mechanism behind how an electron emits (or absorbs) a photon? How does that work?
24. ### B Feynman Diagrams and QED

Thank you! That cleared up a lot of things.
25. ### B Feynman Diagrams and QED

As an extension question, I read parts of the QED lecture. It said that light can take an infinitely different route, but some routes are more likely for light to take. My question is that how does that idea relate to the Feynman diagrams (where 2 electrons deflect off each other because of a...
26. ### B Feynman Diagrams and QED

So... QED is a better, more detailed explanation of electromagnetic forces? It replaces the field theory? I just want to know what QED is, not what limitation it has.
27. ### B Feynman Diagrams and QED

Yeah. But what IS QED anyways? I'm not really talking about Feynman diagrams. I just want to get a gist of QED and how it relates to Feynman diagrams.
28. ### B Feynman Diagrams and QED

I'm new to QED, so I want to have a general grasp of what's going on. I just want to understand it conceptually. Can anyone explain it in a way so a layman can understand?
29. ### B Question about simultaneity

The famous example demonstrating that simultaneity is an non-invariant variable would be the lighting bolts striking a fast moving train. Or a projector at a mid-point shooting off two beams at the same time to receivers on the opposite ends (for the person at rest and not on the train's...
30. ### B Any good resources for a beginner like me?

For the Minkowski diagram, my teacher used "ct" as the unit y-axis and "x" as the unit of x-axis where x is distance. I presume that c is light speed and t is time for the y-axis. I think they are multiplied together? I thought that speed times time is distance/displacement I'm a bit confused as...
31. ### B Any good resources for a beginner like me?

Like I said, I'm new to Special and General Relativity. It really sucks when I space out for 2 minutes in class and for the next 30 minutes I'm completely lost until the teacher brings up a new topic. I'm looking for supplementary materials (online preferably as I'm away from home) that can...
32. ### B Can someone explain to me what's the Schrodingers cat?

Hi, I'm new to this thread. My brother tried to explain the Schrodinger's cat to me but the explanation was vague, I became confused. Can someone explain to me in high schooler language what it is and how it works? Thanks in advance.
33. ### Studying Competing in the International Physics Olympiad

Thanks for the response! I'm planning on working about 30 problems per day each chapter in my textbook. I hope that can fill in my gap in knowledge, and it will click for me. Is that too much or nah?
34. ### Studying Competing in the International Physics Olympiad

As I stated in the title, I'm trying to compete at the physics Olympiad and hopefully walk away with a decent ranking. I am currently a sophomore at a mediocre high school; I'm taking this Olympiad physics class for preparation. The course is once a week for 3 hours that is covering...
35. ### Finding two objects velocity after an elastic collision

Thanks for responding!
36. ### Finding two objects velocity after an elastic collision

Oh ok, I see now. I need to substitute that that equation into the first one. So 7 = v2f - v1f v1f = v2f-7 28 = 3(v2f) + 4(v2f-7) v2f = 8m/s Thus v1f = 1 m/s Thank you!
37. ### Finding two objects velocity after an elastic collision

Kinetic energy is conserved? Sorry, I'm a bit lost. Could you elaborate a bit more? Thanks
38. ### Finding two objects velocity after an elastic collision

Homework Statement A 4-kg block moving at 7m/s makes a head-on collision with a stationary block of mass 3kg. Find the velocities of the two blocks after the collision. m1=4kg, vi1=7m/s m2=3kg, vi2 = 0m/s Trying to find vf1 and vf2 2. Homework Equations Using the conservation of momentum...