Kinematics Definition and 1000 Threads

  1. anthonywsadler

    Simple Work Problem Disagreeing with Kinematics

    I have the following problem: "A box with a mass of 10 kg is accelerated by 10 m/s/s over a distance of 10 meters. What is the kinetic energy of the box (assuming no friction)" Using work... Work = K.E. F * D = K.E. m*a*D = K.E. = 10 kg * 10 m/s/s * 10 m = 1000 Joules However, using...
  2. lion1014

    Grade 12 Kinematics -- Will the car stop before the cliff?

    t= v/a =25.8 m/s / -2.5 m/s^2 =10.1 s therefore, d= vi * t + 1/2at^2 = (25.8)(10.1) +1/2(-2.55)(10.1)^2 =131 m I got the first one right I think, but I don't know how to do b
  3. R

    Unreasonable values for engine torque in vehicle simulation

    I'm trying to simulate the physics of a Toyota Camry during acceleration with a time granularity of 100ms. My simulated conditions are as follows: m = 1590 kg v = 17 m/s a = 1.5 m/s2 η (transmission efficiency) = 0.85 rwheel = 0.35 m Fdrag = 100 N Ffriction = 260 N Faccel = 1590 kg × 1.5 m/s2 =...
  4. wcjy

    Conservation of energy, centripetal acceleration, kinematics

    (a) Using COE, $$mgh = 0.5mv^2 + 0.5I\omega^2$$ I solved it, where $$\omega = 112 rad/s$$ (b) This is the part where I have question or problem. I saw my course mate working and he start of with finding centripetal acceleration. $$a_c = \frac{v^2}{r} = \frac{(r_0\omega)^2}{R_0}$$ Why isn't it...
  5. O

    How to find d2 when given d1 and d, total time, and average velocity?

    I rearranged the displacement formula to d2 = d + d1. I used cosine law to solve for d2 since the triangle is not right-angled but I am not getting the correct answer or angle for d2. The angle I used in cosine law (based on the diagram) was 32+12+90 = 134. d = v(t) = 130(3) = 390 km/h [N 32 E]...
  6. J

    Seemingly Simple Kinematics Question

    Hello, Perhaps I am overthinking this, but I am trying to find the acceleration of the 'pulse rate' in the below plot. Every so many seconds there is a pulse (you can think of this as x displacement). The initial rate between pulses is 5 pulses/sec (you can think of this as velocity). I am...
  7. Amrator

    Relativistic Kinematics: Distance of B When A Coincides with L

    I don't know why I'm so puzzled by this problem; it's only one star. So first, I drew a picture of A and B in the ground frame. Then I drew B and the ground in A's frame. I then used the velocity addition formula to obtain the velocities of both B and the ground relative to A. $$\frac{v_{B}^{A}...
  8. fingerprintregion

    Relativity: Relativistic Kinematics and Dynamics

    I’ve read Beiser’s Modern Physics Chapter 1 and I am able to grasp the general theories but not so much when applying it to problems. I major in Chemistry and would really appreciate any head start/help/suggestions. For number 1 I thought of using L = L0 sqrt 1-v^2/c^2 but can’t seem to find the...
  9. dudu

    Kinematics Question: A motorboat and a log in a stream

    I found vlog=1.9/t and vb-v=1.15/t and vb+v=d+1.15/60.8 don't know what to do now
  10. N

    Kinematics question: Stunt driver jumping his car from ramp to ramp

    Do i use the equation above mentioned to solve it? If i do, am i correct to say that Vx = 90/3.6 cos 30 and Vy = 90/3.6 sin30?
  11. wcjy

    Kinematics, Conservation of energy, momentum

    m1 + m2 = 8 COE 0.5(m1)(u1)^2 + (m1)(g)(30) + 0.5(m2)(u2)^2 + (m2)(g)(30) = 0.5(m1)(v1)^2 + 0.5(m2)(v2)^2 + (m2)(g)(16) Can you check if my eqn is correct? And can you advise what to do after this? I wanted to do COLM but i don't know what is the initial part.
  12. AN630078

    Kinematics Motion with Variable Acceleration

    The displacement of the particle is; s= ∫v dt s= ∫4-3t^2 dt s=4t-t^3+c When the particle is at the Origin, t=0; 0=4(0)-(0)^3+c c=0 So this becomes; s=4t-t^3 The particle next passes through the origin when; 4t-t^3=0 Factor out the common term -t; -t(t^2-4)=0 Rewrite t^2-4 as t^2-2^2 and factor...
  13. Kitanov

    Finding Trajectory of x & y in Kinematics

    I need to find a trajectory x = 4cos(2t) + 3sin(2t) y = 3cos(2t) - 4sin(2t)
  14. aspodkfpo

    An error made in a kinematics question about a spring launcher?

    Genevieve the galah wants to test out her new creation - the Nifty Numbat Launcher. It consists of a large, ideal spring with equilibrium length l1 = 1.7 m and spring constant k=41 N/m. The spring rests upon a ramp of length l1 inclined at an angle β=30∘ to the horizontal. The spring is attached...
  15. Ashelion

    Kinematics Question with weird units

    Would the A = 2.0 ms^(-5/2) affect my answers for parts (a) to (c)? Since I basically ignored the unit ms^(-5/2) and integrated the function to get the ones for velocity and displacement. And as for part (d) explain the dimensions of A; I assumed that the ms^(1/2) comes from the square root due...
  16. K

    Calculating Angular Diameter of an Orbit Using Kepler's Law

    I am confused because the question implies that I need to do some sort of calculation with Kepler's law. I got ##r+d = \sqrt[3]{\frac{T^2 GM}{4 \pi^2} } ## But don't understand why I need this, since I already have the distance and the angular diameter should be ##\arctan (2R/d)## I think I...
  17. D

    Kinematics and vectors -- A heavy box is being pulled using two tractors....

    I solved it using parallelogram law if vector addition but didn't got the correct answer.why? Is their any other way to add velocity vectors. How to do this problem
  18. M

    Conservation of angular momentum and its counterpart for linear momentum

    Hi, I have just joined the forum. Thank you all for being a part of such places so that people like me can get answers to the questions on their minds! --------------------------- I have been trying to understand how a quadcopter yaws. Referring to the figure below which is bird's eye view of...
  19. S

    Kinematics problem - changing coordinates

    Hi folks, See below for a solved question finding the down slope distance of an arrow. How easy would it be to solve this question by making the x-axis the slope direction?
  20. Y

    Kinematics - finding the time when two moving objects meet

    I tried doing (vi)(∆ t) / 1/2(a)(∆ t) = 1/2(a)( ∆ t)² / 1/2(a)(∆ t) That allows you to cross out the two accelerations out and you end with an answer of 20. But apparently, they never meet. I then tried making them into two different equations and using graphing technology (Desmos) and they...
  21. J

    Kinematics and displacement, who is right?

    Hi everyone I have an issue with my physics teacher about a question on displacement. I have inserted the screenshot of the question below. By the definition of displacement, I was sure, and still am sure my answer is correct. But my physics teacher insisted that I am wrong. Please, can anyone...
  22. R

    How Long Does it Take for a Motorcycle to Overtake a Car?

    Here is my attempt at the solution but I got the wrong answer. The right answer is t=16.6s. I know from the book (this is an example problem) that the motorcycle reaches its max speed at t=7.0s. But I don’t know where I made the mistake that is causing me to get the wrong answer afterwords.
  23. J

    Kinematics of deformation (Continuum mechanics)

    Question is extracted from "Ellad B Tadmor, Ronald E Miller, Ryan S Elliott - Continuum mechanics and thermodynamics From fundamental concepts to governing equations". I just got stuck at part (a). I think if part(a) is solved, I may be able to do the other parts.
  24. J

    Forward kinematics model using DH parameters in MATLAB

    5 links (thus 6 frames) and corresponding theta, alpha, d and a values are all given. However, I'm not sure how to start coding the DH parameters to derive a forward kinematics model. I know that I'll have to use matrix operators, but do I just put in the values of the 4 factors mentioned above...
  25. C

    Kinematics equations: Prove that a=vdv/ds

    We know that v=v(x, t) i.e. V is a function of time as well as space coordinate here I have only taken 1D motion for simplicity. By chain rule a=dv/dt= Dv/Dx*dx/dt +Dv/Dt*dt/dt where D /Dx represent partial differentiation along x coordinate. So, a=Dv/Dx*dx/dt +Dv/Dt Here we say that Dv/Dt=0...
  26. A

    Kinematics without rolling or sliding

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

    What is the Linear Distance and Angular Velocity of a Rotating Potter's Wheel?

    A potter's wheel with a 35.9 cm radius rotates with a 2.91 rad/s2 angular acceleration. After 5.37 s, the wheel has rotated through an angle of 77.7 rad. a)What linear distance did a point on the outer edge travel during the 5.37 s? b)What was the initial angular velocity of the wheel? c)What...
  28. jisbon

    Solving for Maximum Speed of Cube: Kinematics & Upthrust

    So, I recognise that: $$ma=pg\left( L^{2}\right) \left( L-y\right) -\dfrac {1}{2}pgL^{3} $$ whereby $$pg\left( L^{2}\right) \left( L-y\right)$$ is the upthrust while the other is mg. So, to find the largest speed of cube, I will assume that acceleration is zero since the acceleration slowly...
  29. A

    Kinematics and angular speed of a collision between a rod and puck

    initial total KE= (1/2)(0.6kg)(8m/s)^2 = 19.2J (0.6kg)(8m/s) = (0.6kg+1.8kg)(vf) vf= 2m/s final KE= (1/2)(0.6kg+1.8kg)(2m/s)^2 = 4.8J I tried to use linear speed=angular speed * radius : thus 2m/s= angular speed * (3.3m/2) angular speed= 1.2 rad/s Apparently that is wrong.
  30. M

    Kinematics Problem: constant acceleration, motion in a line

    I've been attempting to solve this problem for three days now. I have thrown away my old attempts (like, scrumpled up into the bin), but my old attempts involved: Trying to set up simultaeneous equations relating the journeys between EH and FG to find the deceleration, but the reason why this...
  31. B

    Move Stewart platform without Kinematics

    Hello, I've a small project (stewart platfrom) part of another one. I'd like to move my platform with a joystick on X, Y translations and roll, pitch, yaw. Since this is a component of a bigger project, so this part should just move without precise kinematics, I'd like to perform approximate...
  32. C

    Pushing a stalled car out of an intersection

    Hints given: -Start with free body diagram. Use the relationship between impulse and momentum to find the final velocity of the car after he has pushed for time t. -Use a kinematic equation to relate the final velocity and time to the distance traveled. -What is his initial velocity? My...
  33. A

    Rotational torque and kinematics of a rod

    moment of inertia = (1/3) (2.1kg) (1.2m)^2 = 1.0 kgm^2 center of mass= (0.6i, 0j) magnitude of the gravitational torque=9.8m/s^2*2.1kg*0.6m= 12.34N*m position of the new center of mass now : x direction = cos(20)*0.6m=0.56m y direction= -sin(20) * 0.6m = -0.2m change in gravitational...
  34. B

    Projectile Motion Calculator: Find Distance and Final Velocity

    Vx = 10cos(23) = 9.21m/s Vy = 10sin(23) = 3.91m/s -30 = 3.91t + 1/2(-9.8)t^2 0 = t(3.91 - 4.9t) + 30 4.9t = 33.91 t = 6.92s Delta X = 9.21(6.92) + 1/2(9.8)(6.92)^2 Delta X = 298.38m Vf^2 = 9.21 + 2(9.8)(298.38) Vf^2 = 5857.458 Vf = 76.53m/s
  35. D

    Solving Kinematics Problem: V_o & Max Height

    For this problem I tried to find when the binoculars reaches the maximum height. So, (0.75 + 1.28)/2 = 1.015s. Using that information I can solve for the initial velocity. v_o = gt = 9.947 m/s. Then using the initial velocity I can solve for the height of John using the 2nd kinematics equation...
  36. S

    Need help with 2 Kinematics questions (New to forum and physics)

    I am new to physics and these are my last two questions of my homework. I am extremely confused on what to do but I do know that for question 1 I need to create a triangle and solve for the hypotenuse, and for question 2 I believe I need to input my given values into the equation for...
  37. A

    Problems in understanding kinematics

    Hi, I tried to understand kinematics after having an omnidirectional roobt. Some problems stop me to go further. Here I upload some contents of different papers talking about kinematics. For the 1st three pictures, I don't know how equation (8) is from and I am little confused about...
  38. K

    Olympic Kinematics Problem: Reaching the Goal in Time

    Summary: Olympic problem from kinematics Hello, could anyone help me with the following problem? I don't quite get how exactly does it work. After being kicked by a footballer, a ball started to fly straight towards the goal at velocity v = 25m/s making an angle α = arccos 0.8 with the...
  39. A

    Box and a Spring on on an inclined plane

    Homework Statement: A box of mass M=30 kg sits on a ramp which is tilted at angle 13 degrees. The coefficients of static and kinetic friction between the box and the ramp are both 0.12. The box is connected to a spring of spring constant k=9 Newtons per meter. Initially, the box is held in...
  40. A

    How to calculate the kinematics of an object pushed up an inclinex plane?

    Homework Statement: Joe puts on his skis and heads for the slopes. A fresh layer of new snow has fallen, making the coefficient of kinetic friction between his skies and the snow only μk=0.037. He heads for the Starlight Run, which features a long slope at a constant angle of θ=17.8 degrees...
  41. M

    Kinematics Homework Question- Deriving an expression

    I have been attempting this physics problem for a while now. I am not sure how to begin to attempt this problem with the equations of motion formulas.
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