What is Kinematic equations: Definition and 111 Discussions

Kinematics equations are the constraint equations of a mechanical system such as a robot manipulator that define how input movement at one or more joints specifies the configuration of the device, in order to achieve a task position or end-effector location. Kinematics equations are used to analyze and design articulated systems ranging from four-bar linkages to serial and parallel robots.
Kinematics equations are constraint equations that characterize the geometric configuration of an articulated mechanical system. Therefore, these equations assume the links are rigid and the joints provide pure rotation or translation. Constraint equations of this type are known as holonomic constraints in the study of the dynamics of multi-body systems.

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  1. M

    Energy Loss of a ball falling off the lip of a ramp

    Homework Statement This is a Lab: A Ball is placed on a 14cm high ramp and it rolls down to the bottom of the ramp and onto a table where it rolls 20cm (the ramp's horizontal displacement is 16.5cm). After rolling on the table, the ball falls off the table for 76.5cm with a forward horizontal...
  2. F

    Use kinematic equations if acceleration is time dependent?

    Hello forum, The kinematic equations for motion with constant acceleration are: v_f = v_0 + a*t x_f = x_0 + v_0 * t +(0.5) a*t^2 The acceleration a is a constant. Is it possible to use them if the acceleration is not constant but a function of time? For example, a(t)= 3t^2+2? Can we simply...
  3. F

    Kinematic Equations: Vector & Scalar Formulas

    Hello Forum, the kinematic equations for motion with constant acceleration are vector equations which can each be expanded into 3 scalar (or component equations). The vector equations are: v_f = v_0 + a (Delta_t) r_f = r_0 + v_0 (Delta_t) + (0.5) a (Delta_t)^2 r_f = r_0 + (0.5) (v_f + v_0)...
  4. C

    Find the largest initial velocity

    Homework Statement Homework Equations I know that this could be solved through kinematics. The Attempt at a Solution I thought that I could use the range equation to solve for Vo, but since there is an initial height, I don't think that could work. I thought that maybe I could use the...
  5. AntoineCompagnie

    How does the kinematic energy appear in the work integral?

    Homework Statement We call Kinetic energy Ec=1/2 mv^2 its deferral into the work integral gives: \begin{align*} w_{12}&=\int\limits_1^2\delta W\\ & = \int\limits_1^2 \vec F \wedge d\vec r\\ &\underbrace{=\int\limits_1^2dE_c}_{why?} \end{align*} But Why does the kinematic energy appears in...
  6. N

    Time and time intervals when using kinematic equations

    1. A space vehicle accelerates uniformly from 85 m/s at t=0s to 462 m/s at t=10s. What is avg acceleration? How far did the space vehicle move from t=2s to t=6s. 2. Got the avg accel easily enough w basic equation for accel. Problem is conceptual with the displacement portion of the question...
  7. L

    Skating ramp, only height given. Kinematic equations.

    Homework Statement A skater jumps off a quarterpipe ramp and reaches 5m over the ramp. We can assume that he jumps in a vertical line. Find the speed the skater had before jumping off the ramp. Homework Equations https://www.physicsforums.com/threads/introductory-physics-formulary.110015/ All...
  8. L

    Girl running after a bus, kinematic equations.

    Homework Statement Marie is running to catch a bus. The bus has stopped at a bus stop. The bus has the acceleration 0.75m/s^2. Marie has the speed 8m/s. Before the bus starts driving, the space between Marie and the bus is 17.5m. A How long will it take for Marie to catch up to the bus? B What...
  9. C

    Calculating initial velocity using kinematic equations

    Hi! I'm working on a problem for class and am having trouble figuring out how to calculate the initial velocity, which I need in order to calculate acceleration and from there the value of an unknown force. I thought I was on the right track, but my professor reminded me that I need to use the...
  10. L

    Kinematic Equations Used to Find A.) Average Speed & B.)Acceleration

    Homework Statement A truck covers 40.0m in 7.15 s while uniformly slowing down to a final velocity of 3.50 m/s. a.) Find the truck's original speed b.) Find it's acceleration Homework Equations Δx = Vav(Δt) = (V+Vo/2)Δt a=(V-Vo)/(Δt) The Attempt at a Solution Part A.)...
  11. S

    Kinematic Equations for Projectile Motion

    Homework Statement How long will an arrow be in flight if it is shot at an angle of 25 degrees above the horizontal and hits a target 50.0m away at the same elevation? Known: displacement in x-axis: 50.0m acceleration in x-axis: 0m/s2 displacement in y-axis: 0m acceleration in y-axis...
  12. B

    Solve Kinematic Equations for Collision of Carts

    Hey guys how's it going. My physics teacher gave us a challenge problem for extra credit, me needed the extra credit i decided to come here for help. Homework Statement here is the link to the problem itself. http://www.modelingphysics.org/consta/challenge.pdf I have actually done number...
  13. H

    Mastering the 5 Kinematic Equations: An In-Depth Look at Motion Rules

    I know that there's 5 key equations for motion which is: d = (vf+vi/2)t vf = vi + at d = vit + 1/2at^2 vf^2 = vi^2 + 2ad d = vft - 1/2at^2 Correct? But my teacher was confusing me today and he taught us these two other equations: d = 1/2(vi+vf)t d = 1/2at^2 What are...
  14. H

    Calculating Car Acceleration: Kinematic Equations

    Homework Statement You are driving your car and you heavily apply the brakes for a period of 2.1 seconds. The car keeps moving for a distance of 14.6m before it completely stops. What is the acceleration (in m/s2) experienced by the car? Is it truly "acceleration"?Homework Equations 5...
  15. M

    Help with calculating vertical jump with kinematic equations

    Ok, so I'm using an arduino with an led matrix and a homemade pressure sensor to figure out the height of a vertical jump and then display the info back. First I get the amount of time between when the person left the board and when they land back on it. I then divide the time in half and use...
  16. P

    Solve Kinematic Equations for Automobile Braking

    Homework Statement An automobile is traveling on a long, straight highway at a steady 75.0 mi/h (33.3 m/s) when the driver sees a wreck 150m ahead. At that instant, she applies the brakes (ignore reaction time). Between her and the wreck are two different surfaces. First there is 100m of...
  17. P

    Kinematic Equations (Constant Acceleration)

    Homework Statement The speed limit in a school zone is 40 km/h (about 25 mi/h). A driver traveling at this speed sees a child run onto the road 13m ahead of his car. He applies the brakes, and the car decelerates at a uniform rate of 8.0 m/s^2. If the driver's reaction time is 0.25 seconds...
  18. F

    Basic physics logic help - kinematic equations and forces

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  19. D

    Confusing regarding Kinematic Equations

    "A 93kg water skier floating in a lake is pulled from rest to a speed of 13 m/s in a distance of 20m. What is the net force exerted on the skier, assuming his velocity is constant. So I know I have to find the force I'm going to need acceleration, and to find it I'll need to use a kinematic...
  20. A

    Complex number method for kinematic equations

    Homework Statement Objective: 1. For a two-arm manipulator, use complex-number method to derive the displacement, velocity and acceleration equations for the tracing point P. 2. For a two-arm manipulator, use complex-number method to derive the displacement, velocity and acceleration equations...
  21. B

    .Solving for Initial Velocity: Kinematic Equations

    how to get to Vo = the square root of ((xa)/(sin2theta)) from the kinematic equations or form SinTheta =Voy/Vo CosTheta =Vox/Vo just really confused. I am writing a formal lab for my final and what I am asking is find the initial velocity it would take for the object to hit the target as a...
  22. K

    How can i use kinematic equations to solve this problem?

    Hello everyone, This is my first post so I am sorry if this is in the wrong section. I am currently in a rush to finish my homework. I have tried working on it for several hours but I still cannot figure it out. I am mainly trying to figure out how long the object will be in the air. A...
  23. A

    Calculating velocity, time, and Instantaneous speed using kinematic equations

    Homework Statement An inquisitive physics student and mountain climber climbs a 52.0-m-high cliff that overhangs a calm pool of water. He throws two stones vertically downward, 1.00 s apart, and observes that they cause a single splash. The first stone has an initial speed of 2.10 m/s...
  24. M

    Kinematic Equations Rearrangment

    Homework Statement A= Acceleration Vf = Final Velocity Vi = Initial Velocity D= Displacement T = Time Homework Equations D=Vf*T - 1/2*a*(t)2 Solve for T The Attempt at a Solution I need to solve for T: This is what I got as my attempt but it is so very wrong still...
  25. E

    Finding Maximum Height of Two Simultaneously Launched Balls

    This problem has been giving me problems for the past two days and I can't figure it out :( please help. this is my first ever physics class. Homework Statement A rubber ball is shot straight up from the ground with speed v_0. Simultaneously, a second rubber ball at height h directly above the...
  26. A

    Master Kinematic Equations for Physics Problem Solving | Step-by-Step Guide

    Hey guys! New to the forum! :) Anyways, so in Physics class my teacher gave us these three equations on Kinematics. He says that "pretty much everything can be done with these three", and here they are: V(final)= V(0) + AT V(final)^2= V(initial)^2 + 2A(ΔX) and... X(final) - X(initial)=...
  27. K

    Murder Mystery Solution using Kinematic Equations

    I'm new to this site, so let me know if I'm doing anything wrong. Homework Statement I have attached the original problem in a PDF file. I have to read a murder mystery story and pull information from it to plug into kinematic equations and find out who commited the murder. Important...
  28. C

    Kinematic Equations, solving a quadratic gives two solutions?

    Homework Statement Hello, after searching the internet I found this very active community and hope you can help me with my problem. On the Khan Academy website (Which I highly recommend) there are exercises such as Kinematic Equations. I was asked to solve Vi (Initial velocity) so I used the...
  29. L

    Solving the Kinematic Equations using Runge-Kutta

    Homework Statement I am attempting to write a physics simulation program using the kinematic equations and using Runge-Kutta to solve them to determine how an object will move through space subject to certain gravitational forces etc. Homework Equations I have x=vt+(at^2)/2 as the equation i...
  30. J

    Beginning physics question about solving for time using kinematic equations?

    Homework Statement A racket ball is struck in such a way that it leaves the racket with a speed of 5.37 m/s in the horizontal direction. When the ball hits the court, it is a horizontal distance of 2.15 m from the racket. Find the height of the racket ball when it left the racket...
  31. 7

    Solving Kinematic Equations: Acceleration from 100m in 9.77s

    A person runs 100 m in 9.77 s. Maximum speed was reached in 3 s, then maintained for the rest of the time. What was the acceleration during the first 3 seconds? I know that I can find the average velocity, which is 100 m/9.77 s, and i know that initial velocity is 0 m/s. I don't know how to...
  32. D

    Kinematic Equations for a Police Car Giving Chase in 12 Seconds

    Homework Statement 1. A car driving at a constant speed of 75 ft/s passes a police car that is initially at rest. If the police car decides to give chase A) What rate would the police have to accelerate to catch up with the other car in 12 seconds? B) What is the police car's speed at the end...
  33. D

    Kinematic Equations - Why can't I solve like this?

    Ok, pretty basic Physics-101 question. However, I don't understand why my method for solving isn't working. Homework Statement Two cars. Car one is at rest, while the car two is traveling at a constant 16.66 m/s (given as 60 km/hr). At the moment car two passes car one, car one begins...
  34. S

    How Do You Rearrange Kinematic Equations Effectively?

    I already typed a long drawn out post, so I am going to simplfy it. I am having trouble using algebra to rearrange equation. For Example, v=d/t And so, to solve for both t and d, I do the following vt=d/t x t vt=d vt/v=d/v t=d/v I have difficulty with most if not all the other...
  35. M

    Help with integrating the kinematic equations

    Hello, Just wondering if someone can help me make sense of something. I realize it's probably a simple problem, but my math skills aren't the best and I can't see through it. I'm trying to end up with this kinematic equation: X= Xo + Vo(t-to) + 1/2(a)(t-to)^2 And to do this the...
  36. C

    Understanding the .5 in Kinematic Equations

    Homework Statement Knowing and understanding the kinematic equation's variables x1, x0, v0, t, and a, how has .5 been incorporated into the equation? I realized this unknown during lab. Now, as I've nearly completed my analysis, I find that the values I've derived for acceleration should be...
  37. B

    Rearranging the kinematic equations

    The equations for linear motion I've memorized are: 1.) v = u + at 2.) v^2 = u^2 + 2as 3.) s = ut + 1/2(at^2) v = final velocity, u = initial velocity, a = acceleration, t = time, s = displacement In an example my physics teacher uses the equation x = x0 + (v^2-u^2)/2a I'm assuming he...
  38. M

    Kinematic equations - What do they mean?

    I'm in a physics 201 course and very confused about the kinematic equations. Is there anybody out there who can describe what each one means? Thanks, Mike
  39. W

    Kinematic Equations: View List & Explanations

    v = v0 + a*t x = x0 + v*t Is there a page or a website where I can view kinematic equations like this which explains them and list them all down.
  40. S

    Something weird about Rotational Kinematic Equations

    Homework Statement I need to find the average acceleration of a gramophone record. Initial angular velocity, W = 0 Final angular velocity, w = 3.50rad s^-1 angular displacement, 8 = 0.25rad Homework Equations The equation given by the answer is t= 8/w a = ( w - W ) / t the answer is 49.0...
  41. R

    Understanding Kinematic Equations of Motion

    Can anyone help me familiarize myself with the Kinematic Equations of Motion? I need to know them for this summer institute. Thanks, Randeezy
  42. K

    Rearranging Kinematic Equations. Help.

    Homework Statement Homework Equations The Attempt at a Solution The template doesn't really apply to what I need help with. I've missed some school and I need help rearranging Kinematic equations. I am new to physics so please use plain english. Here's the specific one I am having problems...
  43. T

    Kinematic Equations: Position & Velocity at t=2.40s

    Homework Statement Using the appropriate kinematic equations and initial values, determine the position and velocity at t=2.40 s. (x, y)=0, 0 (vi, 0)=(25.0 m/s, 65.0 degree) a.Horizontal Velocity of the initial velocity b.Horizontal/Vertical Velocity at 2.40 s c.Horizontal...
  44. S

    Simple kinematic equations question?

    Homework Statement A 52.2 kg pole-vaulter falls from rest from a height of 3.6 m onto a foam-rubber pad. The pole-vaulter comes to rest 0.34 s after landing on the pad. (a) Calculate the athlete's velocity just before reaching the pad. (b) Calculate the constant force exerted on the...
  45. I

    How can I solve 1-D kinematics problems with limited resources?

    Homework Statement I have a problem worksheet for my 'Physics A' class. It deals with 1-D Kinematics, which we are just getting into so I am not very sure what equations I need to use. I'm not asking for someone to answer them for me, but to maybe give me a list of a few equations that would...
  46. P

    Understanding the kinematic equations

    So I am trying to fully understand how to come about the kinematic equations for uniformly accelerated motion. So v = dr/dt and a = dv/dt How does the math work behind this I know the second is the derivative of the first. dr = v*dt dv = a*dt So dv is the...
  47. F

    Kinematic equations and their applications

    Hello, I have a question concerning the kinematic equations http://www.glenbrook.k12.il.us/gbssci/phys/Class/1DKin/U1L6a1.gif vi and vf stand for initial and final velocity, my question is: do these velocities need to be the initial (t=0) and final (end of the motion)? can't I just...
  48. N

    SUVAT Problems: Why t-x and Not t+x?

    When doing SUVAT problems, why does the item which begins motion later given a time "t-x" where x>0. For example, if dropping a ball, and then dropping another ball 5 seconds later, the first ball's time can be expressed as "t" and the second ball's time as "t-5". Why is it not t+5? Thanks
  49. C

    Motorcycle Kinematic Equations

    [SOLVED] Kinematic Equations This is the question. I have sat here and tried to figure out how to even start this problem for hours. I can't seem to get it through my head. If someone could help me set it up, I can figure out the rest I think. Thanks in Advance. Q. A car and a...
  50. J

    Different values with rotational kinematic equations

    [SOLVED] Different values with rotational kinematic equations Hello everyone, I got two different values for final angular speed when I tried to use the third and fourth kinematic equations. I filled the template here with the problem with my attempts. Homework Statement A bicycle wheel of...
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