# What is Phyiscs: Definition and 63 Discussions

In mathematics, the commutator gives an indication of the extent to which a certain binary operation fails to be commutative. There are different definitions used in group theory and ring theory.

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1. ### Solved: Help with a block sliding down an Inclined platform

Fy = 50cos30 = 43.3N Fgx= 50 sin 30 = 25 N a=Fnet/m 3.0 = Fnet/5 Fnet=15 Ff = m Fn 15=m (43.3) m=0.35
2. ### Seeking insights on careers in theoretical physics and cosmology

TL;DR Summary: Aspiring physicist seeking insights on job prospects, education paths, and salaries in theoretical physics and cosmology. Share your experiences and advice for informed decision-making. Thanks! Dear members of the forum, I'm currently in Grade 11, seeking insights on...
3. ### The order of a video play list

Hello all: As reviewing physics in my spare time , a scientific lecture series caught my eyes , by Dr. Steve brunton on his YouTube channel but had few questions Is the lecture series in correct order ? Second question what is the name of the book that he is using ? Best Regards H
4. ### B Looking for help Understanding Inertia

Just a thread to see how inertia works, just studied the laws of motion, and have been fascinated with it.. could use some help on it tho :)
5. ### I Magnetic field at a point along the solenoid's axis but outside the solenoid

For a personal project, I need to calculate the EMF induced by a solenoid, the problem is, that the secondary circuit where the eddy currents are formed are outside the solenoid's length but still on it's axis. The problem comes when i need to calculate the vector magnetic field inductance at a...
6. ### B Homopolar motor rotation in Vacuum

Hi again, I've found interesting video. Roller homopolar motor : Roller Motor Do you think the motor from 1:08 min Will self rotate in Vacuum/Space (No other forces : Gravitational or Other type.) Thank you in advance.
7. ### Acceleration of the cart on a Ferris Wheel (Circular Motion)

After 3,32 seconds, vt should have varied by 0,695*3,32. I have done a previous exercise where you only needed to calculate the radial acceleration in this scenario. There, I took the vt after the given time, squared it and then divided with the radius. I remember clearing that one, so in this...
8. ### Admissions Chances with a Low/mid GPA but high PGRE and research experience

Hello, and thanks so much in advance for any advice. I’m currently a third year physics undergraduate student who’s looking for what programs I should apply to for my PhD. I’m not sure I should bother applying for anything top 20 but wanted to get a second opinion on my applications...

10. ### Electric arc: How to calculate the required voltage for a light bow?

<Moderator's note: Moved from a homework forum.> Calculate the required voltage to produce a electric arc between 2 iron nails (distance: 3cm). I´ve read in the internet that you need 1 kV per mm. But how can I calculate this value, that I need 1kV per 1mm?
11. ### Make a Thermos: Calculate Final Water Temperature

Homework Statement Hello, As part of my engineering orientation class, my team and I have to make a device that can keep a beaker of water warm. We have a list of materials we can and cannot use, but my team and I have decided on aluminum foil and maybe wood. We don't actually have to build...
12. ### A vertical cylinder fitted with a heavy leak-proof piston wi

Homework Statement HERE IS THE QUESTION A vertical cylinder fitted with a heavy leak-proof piston with diameter 84.0 mm contains air (under the piston) of density 1.59 kg/m3 in thermodynamic equilibrium with the surrounding atmosphere, which is at 100 kPa and 39 oC. Determine the mass of the...
13. ### How many air molecules are there inside the tire?

Homework Statement A car tire has a volume of 10 L and is inflated to a gauge pressure of 30 psi (207,000 Pa) at 20°C. How many air molecules are there inside the tire?Homework Equations N = PV/ kbT The Attempt at a Solution (207,000 Pa )x (0.01 m3) / (1.38 x 10^-21 x 293) =5.12 x 10^23...
14. ### Is seeing believing in physics?

I am new here and I am not going to say I have any formal schooling in physics or electrical engineering. I have been in the automotive field for almost 40 years. What I am getting at is, myself and my research partner came across a very unusual circuit about 4 years ago. We spent about 3 years...
15. ### Solve Tension in Rope: 110 Kg Anvil & 9.81m/s^2 Force

Homework Statement I have a rope held by a hook, which is attached to the ceiling by a chain (with an angle theta), in one side, the rope (with an angle alpha) is attached to a a wall, in the other side, the rope is carrying an anvil of 110 Kg mass in vertical position. What is the tension in...
16. ### Find the width increases when a monoatomic gas is heated

1. The problem statement, all variables and given/known Homework Equations ## \frac {PV1}{T1} = \frac {PV2}{T2} ## The Attempt at a Solution I find that v2 = 330/273 V1 But how can this related to the distance of P travel? Also, as the A gas pressed to B, i think the B gas try to resist. But...
17. ### B Practical use of Bose-Einstein condensate?

I'm not a physicist nor an academic, however, the world around me fascinates me. I was watching YouTube and came across an explanation of Bose Einstein condensate, and thought with less space between atoms that would potentially be a better target for creating new elements. So my question is...
18. ### Calculating Electric Field from Force on a Point Charge

Homework Statement What is the electric field at a point when the force on a 1.20 µC charge placed at that point is = (3.0 î -5.0 ĵ) × 10-3 N? Homework Equations E = KQ/d^2 The Attempt at a Solution I'm having trouble visualizing the question. I attempted to draw it out, but its not making...
19. ### A GR to Naive Physics: Is it Possible?

I get asked a lot of questions like "what is the gravitational field due to xyz curved spacetime" ... and I don't think the concepts match well the way the querant is thinking. However, I was wondering if there is a sort-of way to get to something like that. I would normally think of a...
20. ### I What is "unitary evolution" of something in physics?

What do we mean when we say that a system can't change (in time) because its evolution is unitary?
21. ### A car traveling upward on inclined plane

Homework Statement consider a 3300 lb car whose speed is increased by 35 mph over a distance of 200 ft while traveling up a rectilinear incline with a 15% grade. model the car as a particle, assume the tires do not slip, neglect all sources of frictional losses and drag. find the work done by...
22. ### Admissions Bsc in Physics after Bachelors in Computer Science

Can anyone tell me if its possible to do a BSc in physics and astronomy after doing bachelor's in computer science? I was looking at applying for a Masters in physics and astronomy but looks like BSc is kind of a must because of the lack of training in physics I have. I looked at schools like...
23. ### B How do I calculate the G Force in this certain situation?

Hello, I have a question related to a specific situation. I've been playing a game called Overwatch and while I'm not the smartest there is in physics I'd like to understand it better. In Overwatch there is a character named Roadhog he wields a shotgun and a hook. Using this hook he can launch...
24. ### Teen Struggling to Become a Theoretical Physicist?

I'm 14 years old, and I would like to become a Theoretical Physicist. There is an issue though and I don't know what to do. The problem is in math/science "I have to take biology this year :(" class I am so bored they take the fun out of learning. Also everything is way way too slow I am...
25. ### How Can We Measure the Speed of Light Over a Long Distance?

The main question stems from the answer for this one: If I have a light year long rod and push it on one end, how long would it take for the other end to move? Still Unsure of this answer. Main Question: If I had 2, light-year long conductive rods with a voltmeter attached at the ends then...
26. ### Programs Computer engineering or electrical engineering to physics?

I am currently a computer engineering student , in my second year to be precise. I was just wondering if I could continue my postgraduate studies in physics or anything similar , and will I be better off with a degree in electrical engineering ?. like is electrical engineering closer to physics ?.
27. ### Intro Physics Textbook recommendations for someone new to physics?

Here's the issue: I am a junior chemistry major and the time has come for me to take a physics class called "Physics for Scientists". I have never taken a physics class before and I hear from my peers that not only is this particular subject extremely difficult, but so is the ONLY PROFESSOR...
28. ### Forces on an Object Sliding at 8.0 m/s

Homework Statement An object slides across a table at a constant 8.0 m/s to the right. The net force is... A) zero B) equal to the weight C) equal to the mass times the velocity D equal to the friction force Homework Equations N/A 3. The Attempt at a Solution Bu narrowing it down i don't...
29. ### Differential equation for grav, boyant and drag force

Homework Statement So there is a falling object, you have to take into account the boyant force, the pull of gravity and the drag force A time dependent distance equation is what we're looking for Homework Equations Fd=CdApav2/2 Where Fd is the drag force Cd is the drag coefficient A is the...
30. ### Will this pump work for my artificial irrigation system?

Hi all, I am designing an artificial rain system and was thinking about using http://www.dannermfg.com/Store/Products/Danner/PID-02720.aspx to power it. The goal of the system is to deliver roughly 1 gallon of water per hour to each of the 8 exit points (I will measure this by using a bucket...
31. ### Medical Phyiscs master's program at OSU/OHSU vs. SDSU

Hello forum, I am a soon-to-be-graduated Radiation Health Physics student who plans to study medical physics in the future. I have applied for a few schools and I have been admitted to San Diego State's medical physics masters so far. And I am still waiting to hear from Oregon State/Oregon...
32. ### Determine resonant frequency of an AC voltage source

Homework Statement Given a series RLC circuit, with one R, one L, and one C element, and an AC voltage source with variable frequency, find the resonant frequency experimentally given an ammeter and a voltmeter. Homework Equations The current in the circuit when the circuit is in resonance is...
33. ### How can I improve my skills in finding general solutions in physics?

Hello, few days ago I took an exam in my honors physics class and believe I did not do as well as I did on the other exam. Last exam had a few computational problems and the rest were general solution problems. This recent exam had 8 questions that were all general solution problems as opposed...
34. ### Phyiscs- Beats and frequency problem

Homework Statement Homework Equations fb=f2-f1 or f1-f2 The Attempt at a Solution Well, i know how to calculate the beat difference, but I do not under stand which of the 303Hz or the 297Hz referred to question #4 are the correct initial frequencies before adding the Plasticine...
35. ### Time for Two Balls to Reach Same Height

Homework Statement A red ball is thrown down with an initial speed of 1.0 m/s from a height of 27.0 meters above the ground. Then, 0.4 seconds after the red ball is thrown, a blue ball is thrown upward with an initial speed of 24.8 m/s, from a height of 0.8 meters above the ground. The force...
36. ### Is it too late to start in Phyiscs?

Hi For the last 10 years I've been a web developer and for a few years now I've really wanted to look into moving careers. I have a keen interest in physics ever since school and I wanted to ask people's advice on whether there is a point where it is too late to move into a physics related...
37. ### Complex Kinematic problem for grade 12 phyiscs

a daredevil motorcyclist attempts to leap a 48m wide gorge. At the side where the cyclist starts, the ground slopes upward at an angle of 15 degree. beyond the far rim, the ground is level and is 5.9m below the near rim. what is the minimum speed necessary for the cyclist to clear the gorge[b]
38. ### Higgs boson and the future of quantum phyiscs

Can anybody throw light on the following doubts? 1.what is the implication of the recent discovery of the higgs boson in the quantum physics? Does it support the quantum nature of matter and wave and the uncertainty principle? 2. It is said that Einstein did not accept the quantum theory...
39. ### Physics: Why Water in Car Acceleration is Perpendicular

if water in a container in a car and the car accelerates why the surface of the water is perpendicular to the net force of gravity and fictitious force not to the net of normal and gravitational force?
40. ### Phyiscs, finding components with per. line

Homework Statement You are given vectors A= 5.1 { i } - 7.0 { j } and vec B= - 3.8 { i } + 7.3{j}. A third vector C lies in the xy-plane. Vector C is perpendicular to vector A and the scalar product of vec C with vec B is 16.0. Find the x -component and y-component of vector vec C Homework...
41. ### Inclined Plane phyiscs question

Homework Statement He gives the bike a little throttle providing an applied force of 1.20 kN to propel him up the 25 degree incline. THe combined weight of Chad and the dirt bike is 1.85 kN. If the force of friction is 250 N, determine the acceleration? [b]2. Homework Equations [/b I...
42. ### Complex numbers-roles in phyiscs

How are complex numbers used in physics ? Do they have any physical meaning ?
43. ### What does the ratio c/a mean in solid state phyiscs

What does the ratio c/a mean in solid state physics? I have attached a table with a an example. Cheers
44. ### The hilarious phyiscs of Iron Man

(skip this paragraph if you just want the math) I had some free time today, so I thought I'd toy with the impossible hilarity of the Arc Reactor from the Iron Man films. My first line of calculation was on the magnetic field that would be generated if 1/10th of the power output (3 gigawatts!)...
45. ### What is the force applied by the e-brake to stop the car in 3 seconds?

sue drives her 1452 kg car along a straight road at a constant velocity of 30 m/s [E]. Ger brakes suddently give out. she puts the car in neutral and let's it coast for 25 seconds. The air drag decelerates the car to a velocityof 25 m/s [E]. assume a frictionless surface. PART C IS WHERE IM...
46. ### Simple Math and quantum phyiscs 5 x 0 and e =mc2?

Ok this is probably going to sound like the gibberish of a crazy fool but its been awhile since I have done any deep thinking so I am a little rusty. I recently began wondering if one of the reasons why quantum physics and the standard model of particles have so many weird constants and...
47. ### Q about phyiscs of Liposuction (and Sonolumensence)

I am kind of new here so I am not sure exactly where else to put this question. If the moderators or admins could think of a better place to move this, I would appreciate it: Reading an article by Seth Putterman called "Sonoluminescence: How bubbles turn sound into light"(see **), that he...
48. ### Explanation wanted for a demonstration in MIT phyiscs lec #6

The demonstration: A mass of 2kg is hanged to a string that is hanged vertically from a fixture. Another string is attached to the bottom of the mass and then this bottom string is given a downward pull. Note that the strings used are assumed identical. This demonstration can be found here...
49. ### Parts of an 'information' in phyiscs.

Suppose a physical quantity needs to be represented in pictorial form...for example distance. Such value represented should have 3 parts - 1)Orientation - Or the angle that it makes to the axes of the Cartesian coordinate system under which things are being observed. In the 2 images below...
50. ### Parts of an 'information' in phyiscs.

From what I think, any physical value has at most 3 parts - 1)Orientation - Or more explicitly, the angle that it makes with axis of the Cartesian coordinate system. Transforming will not change this value. 2) Position - This is the translational stuff...exactly from which point to which...