# All Activity

1. Yesterday
2. Last week
3. Earlier
4. That's an initial velocity from a jump. Usain Bolt is looking at his whole body running where 12.27 m/s is a sustained speed.
5. Sense check. Usain Bolt max speed is 12.27m/s. How is Jordan able to obtain horizontal velocity around 25m/s??? http://www.planet-science.com/categories/over-11s/human-body/2012/06/how-fast-is-usain-bolt.aspx
6. I'm not following you, Fizziks. None of the graphed values (k∆x vs. Msinθ) are theoretical. k - must be calculated somehow, based on measurements of force, displacement, and/or the like ∆x - measured M - measured θ - measured sinθ - calculated What theoretical values are you referring to?
7. Right, but it's ultimately a proof of 1 vs. 1, not an empirical derivation of g. You're proving something is itself if you use theoretical values.
8. Graphing k∆x vs. Msinθ would result in a slope of g. Not a slope of 1. But since k must have been calculated, the wording of the rubric makes it sound like this solution wouldn't count.
9. Graphing the empirical k_delta_x vs. Msintheta would work, but not the theoretical. They want you to determine an empirical value for g, not do a mathematical exercise that results in a 1=1 proof.
10. A very interesting question, OP. Color me flummoxed.
11. I'm looking at the AP Mech C practice FRQ: https://apclassroom.collegeboard.org/29/question_bank/create/preview/item/1320757 On part c, the scoring rubric says "1 point is earned for [graphing] a pair of quantities that could be used to determine g - students must graph measured, not calculated quantities." Does this mean that graphing k∆x vs. Msinθ would not earn the point? If so, that would deviate from past AP Exams, would it not?
12. i wanted to know if a frightened cat was kinetic or potential energy, not what your cat did for 7 minutes
13. Oh, so you keep all the values positive. Thanks!
14. See here:
15. Everyone in my household has tried working this problem and cannot come up with the given answer. A force F acts on a cart in motion on a frictionless surface to change its velocity. The initial velocity of the cart and final velocity of each cart are shown. You do not know how far or in which direction the cart traveled. Rank the energy required to change each cart's velocity from greatest to least. Cart A changes from 5 m/s to 2 m/s and has a mass of 2 kg. Cart B changes from 3 m/s to -3 m/s and has a mass of 3 kg. Cart C changes from 5 m/s to 6 m/s and has a mass of 5 kg. Cart D changes from -1 to 2 m/s and has a mass of 4 kg. Does this problem use W = 1/2 mv^2 formula? Does mass matter since it's frictionless and is moving in the x direction?
16. so cool!
17. ## Simple Harmonic Oscillator - Critically Damped

I might start with a resource like this: https://opentextbc.ca/physicstestbook2/chapter/damped-harmonic-motion/ or this: https://www.toppr.com/guides/physics/oscillations/damped-simple-harmonic-motion/
18. Well, in AP Physics class we are using Giancoli 6th edition book. It doesn't have equations for Damped simple harmonic oscillator. I looked at the following link: http://farside.ph.utexas.edu/teaching/336k/lectures/node19.html but I do not know how to get started. The given are Amplitude = .05 m, Time = 3.5 sec, Mass = .58kgs, k = 150 N/m and we nee to find Friction force.
19. ## Simple Harmonic Oscillator - Critically Damped

Hi Muskkan. Damped oscillators are outside the scope of AP Physics 1/2, but happy to help if I can. How far have you gotten so far / where are you getting stuck?
20. Can someone answer this: A critically damped simple harmonic oscillator starts from an amplitude of 5.0 cm and comes to rest at equilibrium 3.5 sec later. The simple harmonic oscillator is made of a .58 kg mass hanging from a spring with spring constant 150 N/m. Assuming the friction force is in the vertical direction, how big is the friction force?
21. how do I find an article on this
22. Badminton is a Sport where players score points by striking a shuttlecock with their racket so that it passes over the net and lands in their opponent's half of the court. It involves various aspects of physics, such as aerodynamics, projectile motion, kinetic/potential energy etc..
23. Tetris Gems Super Combo 547,156 New World Record!!! https://www.youtube.com/watch?v=R01-9wYwht8
24. The one about the ice skater? Can you be more specific?
25. I don't understand the context of the 5th question of the Dynamics- Friction worksheet
26. ## BOOKS: The AP Physics C Companion - Mechanics

Absolutely... want you to be 100% satisfied with your purchase. Refund complete.
27. This PDF version can't highlight, can't add notes, I really regret bought it and would like to return it. I'd rather buy the Kindle version. Can I return it?
28. Tails are not required for kites to fly. Tails are one method of stability. It is not necessary to run to launch a kite. There is a book on amazon.com that answers these questions clearly. It's called, "Kite Physics." It gives a visual explanation of the physics of kites in flight. With 125 pictures, illustrations, and 65 experiments. It answers the questions: Are tails required on a kite? How can I improve the flight of my kite? What are the forces that act on my kite? What changes can I try? Do kites glide? What are some applications of kites that I can explore? How do kites fly?

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