Read about velocity | 495 Discussions | Page 1

  1. B

    2 Carts on a Track Compressed by a Spring -- What are their Velocities?

    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...
  2. V

    Determine time after which 4 persons meet in given scenario

    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.
  3. Strand9202

    Velocity of an Object given its position as a function of time

    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.
  4. dahoom102

    Getting the angular velocity using the angular acceleration graph

    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.
  5. SebastianRM

    Slip Conditions for flow between Parallel Plates

    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...
  6. PolVD

    2D asteroid problem

    Hi everyone! I don't know how to solve the next problem, and if anyone could explain to me step by step how it is solved I would thank you a lot. I know it's not hard, but I'm not seeing how to do it. Thank you in advance!
  7. J

    Using Orbital Energy to Calculate Velocity

    So what I did first was calculate the initial and final potential energies with Epi=-9.433*10^11 m and Epf = -1.503*10^12 m. Then I found change in potential energy, -5.597*10^11 m. Using this I determined the change in kinetic energy, 5.597*10^11. I then added this change to the initial...
  8. C

    What velocity does the particle need to get to point B?

    It was a long time ago I did these kind of problems so I’m a bit rusty. The only thing I can think of is divide it up to two parts one x and one y. In y the acceleration is sin(a)*9.82? Then put that in the equation and solve for t. In x the there is no acceleration so the formula is x=V0*t, I...
  9. K

    I Velocity, barrel length and bore volume

    Hello. How does a bullet propell inside a bore? What determine its velocity? I read that a bullet in cal .44 propelled by black powder from a 3” barrel is as powerful as a .25 ACP, however with a longer barrel, the velocity increase significant. With a 8” barrel a .44 black powder bullet is as...
  10. jeffrey

    Pulley angular velocity problem

    Further given: - every beam is infinite stiff - pulleys are massless - cables don't stretch, no slip, and frictionless. -Every pulley has a diameter D except pulley Q. Pulley Q has diameter 0.5*D So what I don't understand is how to calculate/determine the velocity at R and S. Can someone help...
  11. D

    DV Calculation clarification (rocket booster)

    When calculating the dV available from a rocket booster, the below calculation is used: (ISP . g) . ln(Mass when full/Mass when empty) Is 'g' always equal to 9.81 in this equation, or do you use the actual gravitational acceleration that the booster will experience, at it's given altitude, to...
  12. K

    Help with understanding this momentum problem

    Solution on the link:
  13. J

    I Some Flight Calculations and the Motion of the Earth

    A Problem is posed for a flight from Melbourne to Cairns. Using the formula for rotational speed at latitude - 1) The latitude of Melbourne is approx 38 degrees south with a rotation velocity of 820 miles/hr 2) The latitude of Cairns is approx 17 degrees south with a rotation velocity of 994...
  14. jamiebean

    Direction of resulting displacement

    I do not understand part b. I know that x180/pi changes the value into a degree, but i do not understand what's going on inside the bracket. And how did the equation calculated the direction?
  15. P

    Solving for earthquake transit time via Snell's Law

    I was told to solve the second equation above for x to get l2 and l2, but that only gets me those in terms of other unknowns. I'm assuming I just need to solve t for my knowns, but I keep getting caught up by my unknowns. i.e., solving for x gives x = (l2*L*v2)/(l1*v1+l2*v2). Please note "l" is...
  16. K

    Average speed and average velocity

    So thing that confusses me, is what is the difference regarding the calculation of speed and velocity? In think I should use the formula I wrote above to find the average velocity, but I don't understand what the formula for average speed will be then. By the way, when using the formula above...
  17. Ennio

    I Velocity correction´ formula for the rotation of the Earth

    Let´s suppose we are observing the sun and measuring some spectral lines. Does the velocity correction´s formula for the Earth include the rotational velocity components of the Sun as well? or rather are we basically measuring both velocity contributes of Earth and of Sun together (receeding...
  18. TammyTsang

    Engineering Scaling of units for equations of motions

    In the picture, there is a problem where the t is in units of square root(l/g), and V in square root(gl) I am wondering 1. What it means when time is in units other than time? Does it mean that when solving I have to take time/squareroot(l/g) 2. How did they get square root(l/g). Thank you...
  19. J

    G-force experienced by a jumper, using a DE

    We are given that ##v' = \frac{1}{10}v^2 - g##. I tried using implicit differentiation so that ##v'' = \frac{1}{5}vv' = \frac{1}{5}v(\frac{1}{10}v^2-g)## and set this equal to 0. Hence we have 3 critical points, at ##v= 0##, and ##v = \pm \sqrt{10g}##. Calculating ##v''(0)=-120##, we know the...
  20. A

    Kinematics without rolling or sliding

    I initially thought it is v, because the speed shouldn't change when the tape is on top.
  21. J

    I Translational and rotational velocity

    For a cylinder rolling down an inclined plane, does the tangential velocity of a point a distance R from the axis of rotation equal the velocity of the center of mass?
  22. J

    Particle bouncing between walls

    I thought it would be a good idea to pretend that the walls are stationary and that each time the particle hits a wall, it gets a velocity addition of the velocity of the wall it’s hitting. Using this I ended up at the formula V = initial velocity of particle + n(velocity of left wall) +...
  23. n3pix

    I Converting Velocity Vector Formula from Cartesian Coordinate System to Polar Coordinate System

    I have a little question about converting Velocity formula that is derived as, ##\vec{V}=\frac{d\vec{r}}{dt}=\frac{dx}{dt}\hat{x}+\frac{dy}{dt}\hat{y}+\frac{dz}{dt}\hat{z}## in Cartesian Coordinate Systems ##(x, y, z)##. I want to convert this into Polar Coordinate System ##(r, \theta)##...
  24. Michael_0039

    Α baseball player throws the ball...

    Hi all ! I wonder if I'm right. (From : Fundamental University Physics, Volume 1 (Mechanics) - (Marcelo Alonso, Edward J.finn) Addison Wesley 1967) This is my try: * I have the Greek version of the book and there is no answer. Thanks.
  25. Prabs3257

    Velocity of the center of mass in constrained motion

    I tried getting the velocity of a which by using constraint came out to be 3 and by using the eqn for vcom i got the ans as 3.5 i just want to confirm is this the correct answer
  26. Adesh

    A question of kinematics involving a changing velocity vector

    The statement "at the initial moment of time v ⊥ u and the points are separated by a distance l " gives us a picture like the one which I have added in attachment. As the time passes velocity vector v would gradually change from fully vertical to fully horizontal in order to meet point B. Now...
  27. J

    Doppler Effect Problem

    Pretending the siren is at rest in air: Wavelength = velocity/frequence --> (343 m/s) / 10,000 Hz = .0343m. I don't believe this is the correct way to go about solving the problem, since the vehicle is moving at the start and the siren is not at rest.
  28. msfd

    I Question regarding this Basketball Kinematics Diagram

  29. K

    MATLAB Spring mass impact system in Matlab - How to correct it?

    I am new to Simulink and I wanted to start practicing using a spring mass damper system. My first tutorial was this: Later, I wanted to model a spring system where a mass moving at a known velocity hits the spring. The governing equation and a similar modeling method given in the previous...
  30. S

    Find v(x) of a mass suspended from a spring

    Hi all, I have a problem that I've been grappling with for the past 2 hours. I was confident at first that I found the correct solution, but when I tried to verify I didn't have a constant in my v(x) function. Here is my attempt: I appreciate your help kind internet strangers!