Motion Definition and 999 Threads

I'm in the chapter of Uniform Circular Motion and I have a hard time understating centipetal acceleration. Until now I knew that acceleration describes "how fast velocity changes in magnitude" except projectile motion because when it reaches maximum height then g is going to change the direction...

Homework Statement In circular motion what will be the change in velocity if initial velocity and final velocity is 2 m/s? From the left, in the 3rd diagram, if initial velocity and final velocity is 2 m/ s then what is the change in velocity? t = 5 s Homework EquationsThe Attempt at a...

In the circular motion, What does it mean by this equation s = r.θ?

<< Mentor Note -- New poster has been reminded to use the Homework Help Template when posting schoolwork questions >> A 25.0 kg sled is pulled (assume frictionless) with a force of 15.0 N at an angle of 20 degrees above the horizontal. (a.) How long will it take to pull the sled 25m? (b.) How...

Homework Statement Problem: 5. 37 [/B] With reference to the figure below, the projectile is fired with an initial velocity ##v_0=35 m/s ## at θ=23°. Truck is moving along X with constant speed of 15m/s At instant projectile is fired, back of truck is at x=45m Find time for the projectile to...

I have another question, if I am given a metric and I want to find the constants of motion of that system, then how do I do it? Thanks!

Homework Statement x=Acos(wt+phi) Homework Equations can somebody explain to me please when phi=0. I saw many different questions with many solutions and I can't understand when we have just x=Acos(wt) and when x=Acos(wt+phi) The Attempt at a Solution

Why Space/TIME? I feel Motion affects Time, not the contrary. Thanks for claritication (no Math please).

In projectile motion, we have two components one is x and another is y. x = u cosθ and y = u sinθ But why do I take the' y' component for calculating the 'time of flight' not the 'x' component? y = ut sinθ - 1/2 gt^2, t = 2u sinθ / g

All, I teach physics and would like do a hands-on lab where students are using motors to investigate the concepts of angular velocity and RPM. I've searched Amazon and eBay for low RPM toy motors, preferably those that could be easily powered with a couple of 1.5V batteries. Not much luck...

Suppose a comet F ,at 1 AU distance, is traveling toward a massive body (a neutron star or other) with v= .99 c, suppose also that a = 3 km/s^2 and (to simplify calcs) that it is uniform from there to the star. It will hit the star after ca. 1000 seconds and its speed should equal C: 297*10^9...

I've got a question and can't find any answer on google. So the centripetal force for a particle in uniform circular motion is mv^2/r. This also means that if F > mv^2/r than the particle will get closer to the center and if F < mv^2/r than it will travel further from the center. Say a 5 kg...

This is a question I was looking at based on Relativity and John Wheeler's one-electron universe theory. https://en.wikipedia.org/wiki/One-electron_universe My question is this. The faster you move towards the speed of light, wouldn't everything in the universe contract to a single particle...

I was doing some conceptual problems quickly before moving on to the numerical stuff when I glanced at this answer given in the solutions manual, and it surprised me: Which object has greater speed at the bottom of its fall, object A of mass m dropped freely from height h or object B of mass m...

hi everyone iam new here and i need help in general plane motion when we applied this eq aG=(angular acceleration)*r

I beg your pardon for not writing out the math explicitly in the following. I started to do so, and realized that it would take me hours to debug my attemps at Latex! And I hope that the my explanation is clear enough that it's not needed. I've been working through R.E. Turner's "Relativity...

Homework Statement A metallic spherical shell of mass M and radius R is fully filled with water of mass M is set into pure pure rolling motion on a smooth horizonal surface (w clockwise, v to the right). Now water is freezed suddenly, and the ice sticks with the shell. What is- a) moment of...

<Moderator's note: Moved from a technical forum and thus no template.> Hello all, Earlier today I had an electromagnetism exam, and it seems to me that this problem is unsolvable. There's just too little information given. A proton enters an uniform magnetic field. It's initial speed v is...

I was in physics class a while ago and my teacher had the trajectory of a projectile on the board. he was marking off points on it, and next to each point, right after he marked it off, he wrote 1/2 next to it, then crossed it off while saying "1/2", then proceeded like that, marking off the...

<< Mentor Note -- thread moved from the New Member Introduction forum because of the general nature of the question >> Hi guys, I'm Liszzy newly join physics group. How are you everyone? I'm doing my Canadian diploma in physics and need help from you guys. I've doubt in Kinematic chapter...

Homework Statement charged particule reaches a uniform magnetic B field with a velocity V , and at angle theta with the magnetic field . What is the expression of the relation , expressed as a ratio, of the radius and helical step of the trajectory of the particule . a- 2pi/tan a b- 2pi...

Homework Statement See attached diagram and statement of problem Homework Equations Conservation of momentum ... mv = MV + mv/2 mv/2 = MV V = mv/(2M) centripetal force...centripetal force equals weight at top of circle. MV^2/L = Mg V^2 = Lg V = (Lg)^.5 The Attempt at a Solution Set V = V...

Homework Statement Homework Equations xcxcxcxcxcxcxcxcxcxcxc[/B]The Attempt at a Solution My attempt: Let displacement of A be x m, Let displacement of B be y m, and Let displacement of C be z m. Step2: [/B]a+b+c+d=(a+x-y)+(b+x)+c+(d+z) 2x-y=-z Differentiating LHS and RHS components...

I've seen somwhere a claim that Hamilton-Jacobi euqation is the only formulation of classical mechanics which can treat motion of particle as wave motion. There was something about hamilton prinicpal function, hamilton characteristic function and one of these change in time like wavefront or...

1. Homework Statement This is an olevel question from paper 5090 may/june 2012 paper 12 question number 24 (the snapshot is from another question paper) the answer in the marking scheme is A which clearly I cannot understand. I thought shoulder joints have 3 planes of movementHomework...

Is entering force will be same when a body enter in two box one filled with water and other filled with air. Both boxes have same pressure 7 bar and velocity of body at entering point is 9 m/s

Homework Statement A light rod ##AB## of length ##2a## has a particle ##P## of mass ##m## attached to ##B##. The rod is rotating in a vertical plane about a fixed smooth horizontal axis through ##A##. Given that the greatest tension in the rod is ##\frac {9mg}{8}##, find, to the nearest degree...

I"ve seen several texts that say something like this: Our equation of motion along x is dvx/dt = -g(vx/vt) Integrating this, we obtain equation 178 at this link (pretty near the top; sorry, but I can't figure out how to put the equation here). It's from FitzPatrick's online notes for...

Say, I have a system at rest. I was wondering - how many equations of motion can the system have (without redundancy)? Well, I thought that equating the forces along 2 or 3 different axes would give 3 independent equations. Also equating torques would give some equations, but how many of them...

Homework Statement A cannon can shoot whatever cannons shoot at different angles to the horizon, but with the same initial velocity. At what angle does the cannon shoot to a maximal distance? What would be that angle on the moon? Homework Equations d is the total horizontal distance traveled...

Homework Statement A gun fires bullets each of mass 1g with velocity of 10m/s by exerting a constant force of 5 g weight. Find the number of bullets fired per second (take g=10 m/s2). Homework Equations F=ma M1U1 + M2U2 = M1V1 + M2V2 (conservation of linear momentum) The Attempt at a...

Hello, Does quasars has a proper motion? I searched in different article and sometimes they are considered as objects having a proper motion and other times not. So I want some clarification. in which case can we say that a quasar has a proper motion? Thanks

Homework Statement A sufficiently small steel smooth spherical object is initially at rest at point A on the smooth surface of a finite parabolic curve AOB in a vertical plane as shown in Fig.3-1, where the point O stands for the bottom point, the tangential line at O being horizontal, the...

Using Newton's 2nd law F=ma, If you provide a constant force of 1mil Newtons then an object will accelerate at 100m/s. Using V = U + AT I can say that (speed of light) 299,792,458 = 0 + 100T thus T = 2997924.58 seconds or I can achieve speed of light in 35 days or so. Why is this not...

Homework Statement A river of width 4 km flows at 5 km/h. A swimmer whose speed relative to water is 4 km/h, starts swimming from a point A on a bank. What minimum distance will the swimmer have to walk on the other bank to reach point B directly opposite to A? [/B]Homework Equations Vba = Vb...

Hello, in some exam questions I've looked at it is stated that the pressure distribution is hydrostatic, even though there is fluid motion. (In these cases the velocity has been constant over the section where the pressure is said to be hydrostatic). Is it really possible to assume that the...

I am wondering whether electrons have a net motion against an applied constant electric field in a conductor. Intuition tells me that "of course they should", but so far the math has shown me otherwise. Here are my current thoughts: 1) I cannot rely on the obsolute Drude's model. What's more...

Hi everyone! Sorry for the bad english! Quick question Just to see if I understood: If a person on a spaceship moving at 0.7c in relation to a person in the earth, and both of then agreed they started making microwave popcorn at the same time (like when the spaceship is just above the head of...

Homework Statement A radio speaker produces sound when a membrane called a diaphragm vibrates, as shown above. A person turns up the volume on the radio. Which of the following aspects of the motion of a point on the diaphragm must increase? a) the max. displacement only b) the average...

Hello, I am completing a research project for differential equations class. I am to derive Kepler's three laws and then compare the results of the derivation with real-world data. For Kepler's second law (a planet sweeps out an equal area in an equal time), I was hoping to find orbital data for...

Homework Statement A ##5 ~kg## mass performs circular motion at the end of a light, inextensible string of length ##3~m##. If the speed of the mass is ##2 ~ms^{-1} ## when the string is horizontal, what is its speed at the bottom of the circle? (assume ##g=10~ms^{-1}##) (Ans: ##8~ms^{-1}##)...

Homework Statement https://www.physicsforums.com/attachments/upload_2018-4-29_12-40-30-png.224871/ Homework EquationsThe Attempt at a Solution 1/2mv^2=10 1/2m(ucos60)^2=10 1/2mu^2/4=10 mu^2=80 what to do now?

Homework Statement How to rearrange following equation? Homework Equations f = (1/2pi) square root of (k/m) The Attempt at a Solution (f^2 x m)/ (1/2pi)^2 Is this how i would do it?

Homework Statement Calculate the speed of the block in SHM as it moves through equilibrium position. k= 45.08248265 N/m m of block = 0.505kg T = 0.665s Homework Equations w= the square root of (k/m) ? The Attempt at a Solution w = the square root of (45.08248265/0.505) = 9.448398958 =...

Homework Statement How can I calculate the initial phase in a simple harmonic motion if I only have the amplitude, frequency and angular velocity as data? Homework Equations The formula of the position, in fact they ask me to do the formula that allows to know the elongation depending on the...

Homework Statement In picture, i already solved this problem but i had a question about the bottom question.. So i solved for the acceleration and remember that i got a negative value, i then reasoned with the question and put positive value and was correct.. but then i started thinking about...

Homework Statement A particle moves along a circle in a region of uniform magnetic field of magnitude B=4.0 mT. The particle is either a proton or an electron. It experiences a magnetic force of magnitude 3.2x1015 N. What are (a) the charge of the particle? (b) The particle speed? (c) The...

Homework Statement There is a block of known mass m on a horizontal surface. The block is connected to a pulley via a rope. The other end of the rope is pulled vertically, downwards, with a known force F. The pulley has a known moment of inertia I and radius r. Calculate the acceleration a of...

Homework Statement This question is referring to the classic ball in a loop question where it is dropped from a height and slides into a loop de loop. Derive an expression in terms of theta the velocity of the ball at the time it loses contact with the track. Theta is measured from the...

1. Homework Statement In picture Homework Equations f=ma v^2/r The Attempt at a Solution ΣFy=-mg - Fn = m(-v^2/r) -55*9.8 - Fn = m(-v^2/r) v= 16π/4.5 since circumference = 2πr divide by the rotations time taken per second = 11.17m/s -Fn = 55(-15.6) + 55*9.8 Fn = -319 What am i doing wrong here??