Velocity Definition and 1000 Threads

Homework Statement Is it possible for the instantaneous velocity of an object at some time, t1, to not be parallel to the average velocity over a short time interval, Δt=t2-t1? If it is not possible, explain why not. If it is possible, explain what this situation implies about the motion of...

Hello, I am in need of some clarification on tangential velocity in polar coordinates. As far as I know, the tangential velocity vector is ##\vec{v} = v\vec{e_t}##, where ##\vec{e_t} = \frac{\vec{v}}{v}##. This gives us the ##\vec{e_r}## and ##\vec{e_\varphi}## coordinates of the tangential...

Homework Statement A drunken driver crashes his car into a parked car that has its brakes set. The two cars move off together (perfectly inelastic collision) for 6.0 m. If the mass of the moving car is 1030 kg and the mass of the parked car is 1410 kg how fast was the first car traveling when...

Homework Statement I am reading through Griffiths' Electrodynamics, and I have come to the scenario in the Relativity chapter where in an inertial reference frame ##S##, we have a wire, with positive charges (linear density ##\lambda##) moving to the right at speed ##v##, and negative charges...

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...

Homework Statement Fission, the process that supplies energy in nuclear power plants, occurs when a heavy nucleus is split into two medium-sized nuclei. One such reaction occurs when a neutron colliding with a 235U (uranium) nucleus splits that nucleus into a 141Ba (barium) nucleus and a 92Kr...

Homework Statement Homework Equations E=T+U T=1/2 mv^2 U=∫F⋅dr The Attempt at a Solution Part 1 Work x=x-dot y=y-dot z= z-dot r=r-dot θ=θ-dot [/B] T= 0.5m(x^2 +y^2) 0.5M(z)^2 Changing to polar coordinates T=0.5m(r^2 +rθ^2) 0.5M(z)^2 U=-Mgz E=T+U =0.5m(r^2 +rθ^2) 0.5M(z)^2-Mgz z=L-r...

Homework Statement An archer launches an arrow from coordinates ##(0, 0)## at an angle ##\alpha## and with an initial velocity ##v_0##. There's a target located ahead of the archer and the center of that target is at coordinates ##(d, h)##. At what ##v_0## and at what angle ##\alpha## does...

Hey! I am new on the forum and I joined because I really enjoy physics but I have a horrible teacher. I was wondering if anyone could help me on a question how do I find the velocity at the end of the zipline? how do I find the momentum of the object going down the zipline after it is...

Homework Statement (Translating from a Polish high school textbook, so if anything is unclear please let me know). An object moves on a trajectory described by the parabola ##y=\frac{1}{2\lambda}x^2## such that the ##x## component of its velocity is constant and equal to ##v_0##. The...

Hey there, If body 1, mass M1 has escape velocity V_e1 = (2GM1/r)**.5 but M2 is more massive than M1 is this relation still valid? In this case, the subordinate body really isn't the subordinate body so does this still hold? And r (distance b/t the two) changes not only due to the motion of M2...

Homework Statement Acceleration is defined as the second derivative of position with respect to time: a = d2x/dt2. Integrate this equation with respect to time to show that position can be expressed as x(t) = 0.5at2+v0t+x0, where v0 and x0 are the initial position and velocity (i.e., the...

Hi here is the situation; There's a spherical particle contained with a MEMS sensor (3D accelerometer and gyroscope) moving down a bed. What we want is to estimate the total kinetic energy of the particle. The total kinetic energy has two parts, translational part and rotational part. for the...

Homework Statement A uniform cylindrical wheel of mass ##m_{1}## and radius ##R_{1}## rotates with angular velocity ##\omega_{1}##. It lies a certain distance (along the same axis) from a static wheel of radius ##R_{2}## and mass ##m_{2}##. The wheels are then pushed against each other with a...

I have a question, let’s say I’m holding a long piece of wood such as. 1’ x 6’ plank and I’m rotating it in a circle by spinning around with my hands extended, I suddenly let go, what happens to the velocity of the wood since every point on the wood that is a different distance from the center...

This is something related to my job. There are two components A & B both traveling the same direction but at a different velocity. I can find out the exact velocity of both the components when they just hit each other, thus relative velocity is known. Is there a way I find out the force...

Homework Statement in the attached file Homework Equations Momemtum = mass - velocity The Attempt at a Solution I solved it E. Since object 2 has the larger mass, the effect is less and will move backwards a little bit.

Homework Statement [/B] A skier (mass M = 100 kg) going down a slope with inclination θ = 30°, sliding in a fluid-like snow (viscosity μ = 100 mPa*s) of thickness h = 0.01 m, using a pair of skis, each one with a surface area of As = 0.15 m2, reaches terminal velocity vt after some distance...

Homework Statement I read the expression E=fRT/2 where E is internal energy of ideal gas and f is degrees of freedom, and ##V_{rms} = \sqrt{\frac{3RT}{M}}## Since internal energy for an ideal gas is purely kinetic (according to KTG) I can write 1/2 mv^2 = fRT/2. Now H2 is a diatomic molecule...

I apologize ahead of time for the simplicity of the question, but this has really been bothering me.Given the de Broglie relation, assuming natural units, where ##\hbar = 1##: \begin{equation} \begin{split} \vec{k} &= M \vec{v} \end{split} \end{equation}My question regards velocity and...

Hi, This is my first post on the PhysicsFormus I am trying to design an inlet and outlet for an axial fan and calculate velocity and pressure profiles in the duct. See the sketch attached. The ultimate goal is to carry out a CFD study but I was wondering if there is an analytical solution for...

If talking about a particle rotating around an axis away from it by r. if the particle is moving with constant angular velocity ω. is the linear velocity constant or no? Now what I know is that since we have Vt= ωr, so r doesn't change, as well as ω, so Vt is said to be constant. but I think...

Homework Statement So i have this lab where I am supposed to push a car up an inclined ramp. I record the time it takes for the object to reachest the highest point on the inclined ramp before it goes back down. I am supposed to create a position vs time graph, velocity vs time graph, and...

Homework Statement An object moves at constant speed in a circular path. True statements about the motion include which of the following? a) the velocity is constant b) the acceleration is constant c) the net force on the obj is 0 since its speed is constant Homework Equations hm none...

Hello all, This post is in reference to a previous homework post, found here: https://www.physicsforums.com/threads/show-that-f-gamma-3-ma.338744/ That thread is closed to further replies. Probably because it's nearly 10 years old. That thread is about deriving relativistic force from the...

Homework Statement An electron and a proton are each placed at rest in an electric field of 687 N/C. What is the velocity of the electron 56.5 ns after being released? Consider the direction parallel to the field to be positive. The fundamental charge is 1.602×10−19 C, the mass of a proton is...

Homework Statement 3. (a) If an object's acceleration is zero in one inertial reference frame then is its acceleration zero in all other inertial reference frames? (b) If an object's velocity is zero in one inertial reference frame then is its velocity zero in all other inertial reference...

Homework Statement Use the graph (attached below) to determine the time intervals when the velocity is positive, negative, or zero. Homework EquationsThe Attempt at a Solution The graph is of a position function. Velocity is the derivative of position. Velocity will be zero when the derivative...

https://www.nikhef.nl/~h73/kn1c/praktikum/phywe/LEP/Experim/3_2_03.pdf In direction lab. I wonder why frequency of oscillator set at 50 s^(-1) ? I want to know if the frequency affects the speed of paricles?

Homework Statement What will be the wave velocity, if a string of 100 cm length is in a 10 kg-wt tension forms 9 nodes when vibrated and becomes symphonic to a 50 Hz tuning fork. Given, Cross sectional area of string, $$A=4.95 mm^2$$ & density, $$d = 0.25 g/cc$$? Homework Equations $$...

I have read that the velocity of a body through spacetime is equal to 'c'. Can I therefore draw a spacetime velocity diagram (triangle) with sides: "v" velocity through space...

Homework Statement A ball is thrown upward with a speed v 1. The ball reaches a maximum height of y=h. What is the ratio of the speed of the ball,v 2 , at y=h/2, to the initial upward speed of the ball,v 1 , at y=0? Homework Equations I attached a picture. We are currently studying the four...

Homework Statement Imagine we are observing two aeroplaes from the ground and let their velocities be ##\mathbf{u}## and ##\mathbf{v}## respectively. Assume that the first plane has radar equipment permitting a measurement of the speed of the other plane relative to itself. The velocity so...

Homework Statement The equation is given: v = f(t) = (mg/b)(1 - e^((-b/m)t)) Where v is velocity, m is mass, g is 9.81 and b is a constant of proportionality I need to find the function k(x), where x is distance from said body's initial position. 2. The attempt at a solution v = f(t) =...

Homework Statement Determine the initial velocity of a projectile that reuturns to launch level 10.0 seconds after it is launched and lands 300.0m away from the launch site. Homework Equations Δx=v0xt Δy=v0yt+1/2gt2 The Attempt at a Solution [/B] 300=v0x(10) v0x=30m/s I don't...

Homework Statement Raindrops fall from a broken gutter at 1.0 s intervals to the ground , 19.6 m below Neglecting air resistance and taking g as 9.81 calculate the time for each drop to reach the ground velocity of the drops as they reach the ground speed of drop at the height of 14.7 m I...

Homework Statement My question is, how do I show that speed is equal to group velocity? More information at https://imgur.com/a/m6FwNaG Homework Equations v_g = dw/dk The Attempt at a Solution Part a is substitution, part b uses v_g = dw/dk, part c is multiplication by h-bar, but I am stuck...

Homework Statement How to find the velocity of the air flow around the aerofoil? Homework Equations U - freesteam velocity β - angle of wing camber The Attempt at a Solution To find the velocity of the air flow at each section of the aerofoil, am I right to say that the horizontal velocity...

Homework Statement A photon of wavelength ##\lambda_i = 200## pm hits an electron at rest, and is scattered exactly backwards. Find the approximate recoil velocity v of the electron using momentum conservation. Homework Equations Comptons Scattering: $$\lambda_f = \lambda_i...

<Moderator's note: Split from another thread and thus no template.> I am working on my special relativity assignment right now, and it said to find the velocity of an object when it hits the ground. The height the object is launched at is > 0. Question: comparing that velocity to the...

Why is the velocity in circular motion changing, why not constant?

Homework Statement [/B] So here is my question: I asked you about a solution approach/solution for the following task: Two rail paths cross at an angle of 145 °. With a constant speed of 60 km/h, they just drive along their tracks, and each of them repels steam/smoke flags, which, among other...

Homework Statement The position of a particle moving along the x axis is given in centimeters by x = 9.35 + 1.03 t3, where t is in seconds. Calculate the instantaneous velocity when the particle is midway between its positions at t = 2.00 s and t = 3.00 s. Homework EquationsThe Attempt at a...

Homework Statement I'm simulating a warehouse (in Unity) where forklifts and other vehicles transport stuff from point A to point B. The routes are modeled as a graph with vertices and edges. Every transport is saved as a task in a backend system with the relevant data such as starting time...

Homework Statement AB is a rod of length 10 m that is leaning against the wall. Given variables are shown in the diagram. Find angular velocity of A wrt B. https://imgur.com/a/8bEdYhN I have a doubt in one step that I will highlight in "The attempt at a solution" part. Homework Equations...

Earth is moving through space. If I throw a ball straight up, it falls down to me and is not left behind. This is obviously because it already carries the momentum of Earth's movement. But if I fire a photon straight up, does it also carry a velocity component in direction of Earth's movement...

Hello Everyone, I am brand new to this forum and I am currently doing "student research project task" where I need to conduct my own experiment basically. I am currently struggling to find a formula for an impact velocity. I hope there is someone in this forums that could help me. What I...

Hello. Today I've thinking about limit velocity and speed of ligth. We know that material particles can't achieve that speed, also when the speed of particles increases your own clock walks slowly. In the particular case of ligth your speed don't move anything. This it a explanation of why...

Homework Statement We're supposed to convert a position-time graph to a velocity-time graph to an acceleration time graph. These are the values for the position-time graph: Homework Equations m = y2-y1/x2-x1 The Attempt at a Solution I found the slopes for each time which were 5, 8.5, 17...

Homework Statement A particle starts from x_0 = 14m at t_0 = 0 and moves with the velocity graph shown What is the object's position at t = 2 s? Homework Equations Area under velocity time graph is the displacement of the particle. The Attempt at a Solution The part that confuses me is where...