Velocity Definition and 1000 Threads

Many of us know about velocity stacks. It's a proven fact that velocity stacks can enhance the performance of internal combustion piston-cylinder engines. I want to know if a velocity stack is added at the upstream (just before) to a blower/fan, whether it can enhance the performance of the...

I'm confused whether Hubble's Law applies to objects near the cosmological horizon (CH). I'm told that objects asymptotically approach the CH and freeze there (v -> 0) in the same way that occurs during in-fall towards a black hole. But Hubble's Law says that velocity is proportional to...

Something seems wrong with my use of velocity addition: A fly of rest mass ## m_{0} ## in your reference frame (say a platform) is posed in a train passing with a velocity ## v ## relative to the platform. The fly mass is now for you ## m_{1} = m_{0} \gamma(v) ##. Now in the train the fly is...

Torque appiled by smaller disc = mga emf of disc due to B = Bwr2/2 Current I = Bwr2/2R force = IBr = Bwr3/2r torque = rF = Bwr4/2r mga = Bwr4/2r

If the crawling insect were stationary at a certain instant of time, then it would have the same angular velocity as that of disk, which is w in a clockwise direction. But now it's velocity at any instant is the vector sum of velocity due to rotation and the velocity it crawls at. My attempt is...

Let me start be making a small sketch of the problem, shown to the right. If the range of the projectile on a still day ##R = v_{0x}T##, then on the windy day the range becomes ##R+2H = v'_{0x}T = (v_{0x}+v_w) T##. Since the maximum height attained by the projectile ##H =...

I was watching a video about jet engines, and it was obvious for me and for the instructor that if we compress air at high speed from the gas turbine inlet, then after multiple stages collide with the turbines blades inside, the body will move in the sense of difference in velocity, so forward...

In special relativity, when writing the relative velocity between two inertial observers v=dx/dt, I suppose that "dt" is a coordinate time interval? But as it is not measurable, is the velocity correct and the same for both observers if each one uses his proper time intervals?

We know temperature is a measure of average kinetic energy of molecules/particles of a system. Now if a car starts to move, its velocity increases so does its kinetic energy. Therefore all the molecules are gaining velocity too. Shouldn't this increase the temperatre as average kinetic energy of...

So i know the total time is 8.6 s t1 + t2 = 8.6s And from the (v^2 - v0^2 = 2as) i will get that after 15m the velocity which is also the highest velocity v^2 = 30a And then after that the velocity will be constant (s = v*t) 45/t2 Now i am stuck here because i have 3 equations but 4...

a)What is the total energy in the system? Only energy acting on the system assuming the track is level and there is no potential energy of the carts, is the potential energy of the spring. Comes out to 7.8125 using the potential energy of a spring equation. b) What are their velocities if the...

So for the formula, u'=u/(δ(1-(uv)/c^2) u=2.06E8 and v=0. I am only looking at the y components here. Since v=0 it really becomes u'=u/δ or u'= u*sqrt(1-(u^2)/c^2)). Anyways when I plug this in I am getting 1.49E8 when the answer should be 0.951E8. Am I not using the correct formula here?

53 rpm equals 5.55 rad/sec multiply 5.55 by 2pi to get angular velocity of 34.8717 Is the answer 34.8717? What should I have done to more accurately solve the problem with a better understanding? What other steps should I take when solving similar problems? and lastly, Is the mass relevant...

I have a fan that consumes 60 W and blade diameter is 12 inch. If it's just 60% efficient, then the velocity of air coming out of it is around 9.5 m/s. I also have a nozzle inlet of which fits the fan and the diameter at the throat cum exit is 3.5 inch. I want to know how to measure the velocity...

For a steady, non-viscous and incompressible flow, one can apply both Bernoulli's principle (no potentials) as $$p+\frac{\rho v^2}{2} = p_t$$ where ##p##, ##\rho,##, ##v##, and ##p_t## are static pressure, density, flow velocity, and total pressure, respectively, and continuitiy principle as...

For this question the ball is rolling without slipping so that means the velocity of the point of contact is zero. Does that also apply to the acceleration of the point of contact? Because that’s what I assumed and I applied the relative acceleration formula above and use the starting point to...

The point of confusion is deciding the direction each persons sets out in i.e. velocity direction of each person. Knowing this will probably help in getting the solution. At t=0, I can say that velocity of each person is as shown in diagram below.

Hello everyone, I'm trying to solve a problem from a textbook suggested by a fellow member here: To help me visualize the problem, I made the diagram below (not necessarily to scale or accurate, just an organizational aid): The textbook gives a simplified equation of...

I don't know the distance or the horizontal velocity so I can't find any logical solution

So for this question I got the right angular velocity. But I don’t get the same velocity for point A. I don’t understand why it’s cos30, problem asked for V_a when theta = 45 so I used cos45. I have my work below.

I am very confused when textbooks say the direction of Angular velocity is perpendicular ot radius and theta for that matter direction is in perpendicular direction. I know this comes from cross product rule but what is the meaning of Angular velocity and Angular momentum directing in upward...

First, I calculated the velocity of the object with regards to earth, which is: $$v'=\frac{V-v}{1-\frac{vV}{c^2}}=0.34c$$ Now, the problem is solved if I consider the length ##l=45m##(so by calculating the ##\gamma## factor with ##v'##) to be the proper one... but since it's measured by the...

I try to resolved with my knowlegde of the dynamic class: Acceleration is known to be the derivative of velocity with respect to time. a = dv / dt; so that dv = a dt Replace: dv = (2.4 - 0.6v inch/s^2) dt Then: dt = dv / (2.4 - 0.6v inch/s^2); we integrate t between 0 and 2; v between 0 and v t...

This is a practice problem so I know that the answer is 750 m/.s. Not totally sure what to do with the friction or if any of my listed equations are relevant here but here goes what I've tried: .45 kg = v(0.8 sec) + 1/2(-9.8 *0.1435) * (0.8)^2 .45 kg = v(0.8) + 1/2(-1.4063) * 0.64 .45=v(0.8) -...

My doubt is whether its correct to assume that the exhaust is having the velocity of truck when it comes out of the exhaust pipe. So, I am not sure if Ve = Vt. Should not the exhaust come out in a south direction from exhaust pipe since truck is moving in north direction? If yes, then it cannot...

The solutions used the spend of the wheel and its radius to find the angular velocity. I’m confused because I thought to find angular velocity you use the speed at the points of the radius not the translation speed of the wheel itself. Can someone explain this to me please

The problem: Visualising the problem (My question is with regards to this): Why is the above set-up correct? In the above diagram, S would be moving at velocity -v relative to S', instead of v. Is this because the question says "speed v", and so we can set the direction as such? Why would the...

Angular velocity ω is by definition the runned angle dθ per time dt elapsed: ω=dθ/dt. If the time elapsed in the center of the Earth is dt, the dilated time elapsed on satellite is dt′. What is the satellite's angular velocity? Is it dθ/dt or dθ/dt′?

I calculated as attached and got it right. However, I just wonder why we can't use conservation of energy as the question has already specified 'frictionless', meaning no energy loss and energy distributed to the rotation only.

Hi, I try to find the velocity for a oil drop. I found the forces. ##F=ma => m\frac{dv}{dt} = \frac{4\pi a^3(\rho - \rho_1)g}{3} - 6\pi n a v## with v on the right side, I don't see how to get the solution. I found the solution on few websites, but without the path to find the solution from...

I sent the work divided by two equal to the velocity part of the problem then got stuck.

Hi guys, I don't really know how to solve this problem. The point is finding ##\omega## when ##m_2## passes from ##m_1##'s original position. Ideally, I'm thinking about some conservation of energy/momentum to apply here, but I'm quite confused. Any hint?

The answer is tD = [D_0 - 3/4ct - 1/2ct] I just have 2 questions. I realize for 2 vectors approaching it is negative for distance and for velocity positive. What be the rule for time? How do I find vector answers for velocity and distance and time? I am confused why I have "td = ..." ? Can...

$$\tau _{01} = 10 \tau _{01}$$ If I calculate ##\frac{\tau_{p1}}{\tau_{p1}}## and set z=d=1cm I do not know how to continue from there as I can't solve the equation without knowledge of τ0 for D. $$\frac{\tau_{p1}}{\tau_{p1}} = \frac{\tau_{02} \cdot 10}{\tau_{02}} \sqrt{\frac{1+\frac{d^2 \cdot 4...

##ω = \frac {k} {\sqrt{φ}}## What is the angle between acceleration and velocity after 1spin (2π radians)? First I decided to find out what is the angular acceleration: ##α = \frac {dω} {dt} = \frac {dω} {dt} \frac {dφ} {dφ} = \frac {dω} {dφ} ω \implies ##after integrating ##\implies α = -...

Attached is the problem and my work through the problem. I got the problem correct, but my teacher said this could be done quicker on a calculator. Any idea how it could be done quicker.

The answer here is A What i did is getting the area as follows, 2×4×1/2 +3×-6×1/2 +4×-6 = -29 and then use this Δω=ωf-ωi -29=ωf-5 ωf=24 but there is no such choice.

Velocity addition paradox: In observer A's frame, observers B and C move away from him at the speed of light c, B to the left and C to the right. In B's, frame A and C are both moving away from him at c, i.e. at the same speed. In both A's and C's frames they are moving at different speeds...

A body on a circular orbit in the field of a central force (satellites in gravity field of Earth; a charge in a magnetic field) is subjected to a force which is always perpendicular to its initial velocity v, hence in a time period dt it acquires an additional velocity dv, which is also...

Hi, I was given this problem saying that a ball is thrown vertically up in the air and returns to its initial position after 4 seconds. The acceleration due to gravity is given to be equal to 10m/s^2. I tried to attempt this problem by using the equation : v^2 - v0^2 = 2ah by considering...

In Griffith’s section 10.3.1, when proving why there is an extra factor in integrating over the charge density when it depends on the retarded time, he makes the argument that there can only ever be one point along the trajectory of the particle that “communicates” with the field point. Because...

This is more of a conceptual question. To find the horizontal velocity as a function of time for the above wave function, you take its partial t derivative and insert x=4. In other words the function would be -2.4sin(1-12t). Im wondering why you take the partial t derivative and not to partial...

I think the answer is 6.2 but I also got 40m/s. Which one is right?

My book uses ##1/2m_1v_{1c}^2+1/2m_2v_{2c}^2=1/2m_1v_{1c}'^2+1/2m_2v_{2c}'^2## to show that the angles of deflection of the collision between two particles are the same in the centre of mass frame. However, I am doubtful that one can apply the conservation of energy to a "moving" system because...

1.)##\dot{\vec{r}}=\dot{x}\hat{i}+\dot{y}\hat{j}+\dot{z}\hat{k}=\dot{r}\hat{r}## since the unit vector is constant 2.) ##\dot{r}\hat{r}=\frac{x\hat{i}+y\hat{j}+z\hat{k}}{\sqrt{x^2+y^2+z^2}}\frac{\dot{x}x+\dot{y}y+\dot{z}z}{\sqrt{x^2+y^2+z^2}}##...

The problem states: Two parallel plates separated by distance h, the plate at the top moves with velocity V, while the one at the bottom remains stationary. My initial approach was: I considered, ##du/dy = V/h## and for the shear stress ##\tau = \mu \frac{\partial u}{\partial y}## For...

Heres how I tried to set up the problem. I took the laboratory to be S and the frame of the particle whose speed we know to be S', so that the speed of S' relative to S is u = 0.65c. Also, by convention, S' moves to the right of S, so that S moves to the left of S'. Next, we know that the...

Does mean velocity of particle equal group velocity of wave packet in QM?If they do not equal which of them is classical velocity?