Motion Definition and 999 Threads

A mass m = 0.15 kg is attached to a massless string and rotates at constant speed v = 4 m/s in a horizontal circle of radius 2 m. The tension T (in N) in the string is: (a) 1.1 (b) 1.9 (c) 2.4 (d) 3.3 (e) 4.9 I would assume that first I calculate the centripetal acceleration by using v^2/r =...

Homework Statement An object of mass m is rotating, hanging from a string of known length l. The string is attached to a pole, which rotates with a known angular velocity ω and forms a to-be-determined angle α with the string. Find α. I think I have solved it (the numbers match the results of...

Homework Statement If I have an object with mass M. Place it on a spinning disk at radius R and the coefficient of friction is μ what is the maximum velocity I can spin the disk without the object slipping? I have the actual values for the problem, but I'm much more interested in how to get...

The metric expansion of the Universe does not seem to cause some of the mechanical effects typically associated with motion (commute) of massive objects through space. For example, distant galaxies can be "flying away" from each other at speeds exceeding the speed of light. It seems that space...

Homework Statement Gravity causes a centripetal force that allows satellites to travel around planets. How fast must a 102-kg satellite travel to maintain a circular orbit 352 km above Earth's surface? Homework Equations F=m(v^2/r) -----> (F/m) x r= v^2, then square root F= force m=mass...

Hello The following thought is confusing me a little. Let say we have sphererical planet with a certain mass and radius fixed in space. Now we have a point particle that at time t0 has a velocity vo that is perpendicular to the vector from the center of the plant to the particle and has a...

In circular motion 1) V = rw and ##\vec V## = r ω##\vec e_{tan}## 2) a = rα and ##\vec a## = -##\frac{v^2}{r}####\vec e_{rad}## + rα##\vec e_{tan}## Where ##\vec e_{tan}## is the unit vector along the tangent in increasing direction of θ And ##\vec e_{rad}## is the unit vector along the radial...

Hi all, been a while since I studied physics but I saw something that I found strange, This device: https://researchfrontiers.uark.edu/good-vibrations/ from University of Arkansas A free floating graphene sheet extracting energy from brownian motion and converting that to electric current...

I need help understanding what kind of problem this is at all, since I'm really lost. I'm missing the specific topic name (I called the topic "circular motion" because it's got something to do with it, but maybe it has a more specific sub-topic name), probably missing key formulas, and generally...

Let's imagine a situation where we have a wheel of mass ##M## and radius ##R## on a frictionless surface, and we apply a force ##\vec{F}## as shown in the diagram. The force will produce both linear acceleration of centre of mass ##a## and angular acceleration ##\alpha##. The wheel starts to...

Homework Statement Two parallel plates located at a distance "L" from each other they maintain a potential difference "V" because of a battery (as shown in the picture). Through a small hole, made in bottom plate, electrons get into system (with mass "m" and charge "-e"), with velocity "v" and...

How can I calculate the trajectory of an object knowing the initial conditions and the function F(x,y)? For example, a object orbiting a planet or two electric charges orbiting each other.

Homework Statement Solve problem 8.1, but using force and torque rather than conservation of energy. (Image of 8.1 attached) Homework Equations T = f x d f = ma The Attempt at a Solution I think I might have to find the torque on the disk, which I’m guessing would be 2mgr - mgr, but I’m...

I have just begun my journey in Classical Mechanics with the book "An Introduction to Mechanics" by Kleppner and Kolenkow. I find myself stuck at Newton's first law. The book presents Newton's first law as follows: "Newton's first law is an assertion that inertial frames exist." The book also...

$$\tiny{243.13.01.18}$$ $\textsf{The following equations each describe the motion of a particle.}\\$ $\textsf{For which path is the particle's velocity vector always orthogonal to its acceleration vector?}$ $\begin{align*} \displaystyle (1) r(t)&=t^8i+t^5j\\ (2) r(t)&=\cos(8t)i+\sin(2t)j\\ (3)...

<Moderator's note: Removed template prior to moving it from Homework.> I am looking at centripetal acceleration, and I know that even at a constant speed the object is acceleration because its velocity is changing. But I don't understand how it is changing, like when is it negative and when is...

Vibrations - Modelling system, equation of motion Hi, In the first question (question 4) in the attached file, how would you go about modelling the system and finding the equation of motion? All those masses are confusing me, I don't even know where to start. I don't know whether the angle...

I am trying to create a momentum trap to calculate the velocity of a projectile when it hits the trap. It essentially consists of a plate if known mass at the bottom of a pendulum of known radius. When the projectile hits the plate, the degrees that the pendulum rotates are recorded. I believe...

Homework Statement I'm not asking for a full on solution to my question, but instead wanted to know what was the difference in these two questions. So, here are the two questions 1) A space station of radius 90 m is rotating to simulate a gravitational field. What is the period of the space...

Homework Statement The maximum speed with which a car can take a circular turn of radius R is v. The maximum speed with which the same car, under the same conditions, can take a circular turn of radius 2R is A. 2v B. v√2 C. 4v D. 2v√2 Homework Equations v = (2πr)/T The Attempt at a Solution...

Homework Statement The following question involves a torque acting on a particle in rotational motion. It provides practice with the various equations for angular velocity, torque etc A particle of mass ##m## initially has position...

Homework Statement Homework Equations F = mv^2/R The Attempt at a Solution I got that T1max = T2max because when i plugged into my formula for centripetal force, i get that both ropes end up with mv^2/R which means they are equal everywhere... Is this correct?

Homework Statement Hello! I have 2 bodies initially at rest, of equal masses with the distance between them a and coordinates ##(a cos(\theta),a sin(\theta))## and ##(-a cos(\theta),-a sin(\theta))##. If we denote ##a_x## and ##a_y## the horizontal and vertical distance between them they...

Homework Statement The differential equation of motion for the simple pendulum can be shown to be ##\ddot {θ} = -(g/L)sinθ##. Given that L=9.81 m and that the pendulum is released from rest at θ=60deg, determine the time required for the pendulum to reach the position θ=0deg. Use Δt=0.10s, and...

Homework Statement Assume the roller coaster cart rolls along the curved track from point A to point C under the influence of gravity. Assume the friction between the cart and track is negligible. What would be the direction of the carts acceleration at point A? (The question in the image does...

Homework Statement A child sitting in a tree throws his apple core from where he is perched (4.0m high) with a velocity of 5.0 m/s [35 degrees above horizontal], and it hits the ground right next to his friend. A) How long is it before the apple core hits the ground? B) How far from the base...

Homework Statement Where does T2cos(theta) come from ? Isn't mv^2/R the centripetal force which is the tension of rope 2? Homework Equations Fc = mv^2/R 3. Solution Wait! The horizontal component of the circle is the centripetal force? So that part is mv^2/R? I got confused and thought...

Assume we shoot a space shuttle of mass m to space. We know it affects the Earth's mass M by decreasing it to M2 = M-m. Assume that the gas pillar that the space shuttle shoots has no effects on earth, what would be the theoretical effects on kinetic energy, momentum and velocity of the Earth by...

Is there any way to synchronize two clocks already in relative inertial motion? If so, how? And I am not sure exactly what “synchronize” would mean in that context. Maybe it would mean that their readings, or at least their running rates, would match when their relative motion was stopped? There...

How are we able to move trough the aire if the air exerts a force equal to the friction we use to push us through air? I´ve had this problem in my mind since some days now. I did this picture: url: https://www.kn3.net/60DAC45480AJPG.html

I found this interesting problem on the internet, but I think there is not enough infromation to solve. "At the 1998 Punkin Chunkin World Championship, a pneumatically-driven device called the "Aludium Q36 Pumpkin Modulator" was able to project a 3.6-4.5 kg (8-10 pound) pumpkin intact for a...

I am very confused about angular velocity ω and why its used in simple harmonic motion. ω is described as θ/τ but when it comes to masses on springs, there is no angle - it is zero. Angular velocity comes from circular motion but the motion of SHM is not circular. My confusion is even greater...

Homework Statement You hold a small ice cube near the top edge of a hemispherical bowl of radius 100 mm. You release the cube from rest. What is the magnitude of its acceleration at the instant it reaches the bottom of the bowl? Ignore friction. Homework Equations ΣF = ma Fg = mg The Attempt...

I am finishing up a lab write up for conservation of energy, where we launched a projectile into the air and measured the initial velocity and height of the projectile. ( 10 trials) One of my questions asks if I wanted the ball (projectile) to travel twice as high, how much faster would it have...

Hello, I have a doubt about the Complete Set of commuting observables (CSCO) in the cases when there are a magnetic field ##B## in z. The statement is find the constant of motion and CSCO for a particle of mass m and spin 1/2, not necessary a electron or any atomic particle. I know that the...

Homework Statement A hunter aims a high velocity semi-automatic rifle at a moose that is 500.0 m away in a direct line of sight. The moose stands 40.0 m below the horizontal in a depression with a bog at the bottom. The muzzle velocity is 2500.0 feet per second and the sight on the rifle is...

Homework Statement The speed of the pendulum bob remains constant as it travels around the circle (a) Over one complete circle, how much work does the tension force F do on the bob? (i) A positive amount; (ii) a negative amount; (iii) zero. (b) Over one complete circle, how much work does...

Homework Statement Homework Equations ## v = r \omega## The Attempt at a Solution Velocity of point B= ##v_B = 4 \times \omega = 4 ## m/s Since the separation between B and C is constrained to be a constant, Velocity of B along rod = Velocity of C along the rod ## \Rightarrow v_B \cos \theta...

1. Homework Statement You have two masses moving across a frictionless surface, yet there is friction between the two masses. Mass 2 is on top of Mass 1 A force is applied to m1 which causes It to accelerate at 6 m/s2 and the friction between the two masses causes m2 to accelerate at 4 m/s2...

< Mentor Note -- thread moved to HH from the technical physics forums (because of a forum issue), so no HH Template is shown > There was a huge explosion, one small piece of debris was launched upward at v=5.3 km/s. Calculate its maximum altitude. a) Develop an expression for the maximum...

does mass affect the motion of the vertical upward, vertical motion down, free fall motion, and parabolic motion?

Homework Statement A football receiver running straight downfield at 5.5m/s is 10m in front of the quarterback when a pass is thrown downfield at 25 degrees above the horizon. If the receiver never changes speed and the ball is caught at the same height from which it was thrown find initial...

Hello everybody, I Am Meaningless and I had this doubt when I was reading some illustrations based on questions in Particle mechanics. So the Question was, A particle is attracted by a force to a fixed point varying inversely as (distance)^n. If the velocity acquired in falling from an...

Two small blocks, each of mass m, are connected by a string of constant length 4h and negligible mass. Block A is placed on a very rough tabletop as shown below, and block B hangs over the edge of the table. The tabletop is a distance 2h above the floor. Block A is then released from rest at a...

Homework Statement A 2 kg tetherball swings around a vertical pole attached to two ropes each at a 30 degree angle from vertical. Each supporting rope is 1.5 meters long, and the ball travels at 8 m/s long. Homework Equations The question doesn't ask what they're looking for, so I assume they...

See attached photo please. So, I don't get how equations of motion derived. Why is it that x dot is partial derivative of H in term of p but p dot is negative partial derivative of H in term of x.

Hi There!, I'm here just to know an answer to a question that is bothering me for a while now. We know that motion of a body under the influence of central force with given center [say A] is planar . I was thinking whether this is possible even when body is allowed to move under the influence of...

Greetings all, I apologize for joining your forum just to inquire about something that should be relatively simple, but you seem like a group of physics geeks able to articulate coherent arguments, and I need someone/s to help me see a different perspective on how to make an argument. For the...

Homework Statement An object with mass m = 2 kg is moving in a uniform circular motion with radius r = 2m as shown in the figure. It takes π seconds for the object to travel from θ =0 to θ = 180 degrees. What is the distance traveled by the object in 20 s...