Kinematics Definition and 1000 Threads

  1. R

    Kinematics question - An automobile accelerating and braking

    kinematics question -- An automobile accelerating and braking Homework Statement According to recent test data, an automobile travels 0.250 mi in 19.9 s, starting from rest. The same car, when braking from 60.0 mi/h on dry pavement, stops in 146 ft. Assume constant acceleration in each part...
  2. S

    Kinematics: Projectile Motion, Constant Acceleration

    Please help. I think I may be over thinking this problem because it looks very simple. Homework Statement Determine the minimum initial velocity, v0, and corresponding angle, θ0 needed to kick the ball just over the 3m high fence. x = 6m y = 3m Homework Equations X: vx=v0x x = x0+v0xt v0x...
  3. MarkFL

    MHB Fallin' staR's question at Yahoo Answers regarding kinematics

    Here is the question: I have posted a link there to this topic so the OP can see my work.
  4. O

    Algebraic Approach to Calculating Time for an Object to Fall from a Given Height

    Hey guys so I have a quick question about the algebra for a question like this. I personally like to do the algebra first before I plug in the numbers so I have question for this one where it seems would be safer to plug in the numbers first? So won't be to tough, A book falls from a...
  5. SamRoss

    Looking for a clear distinction between laws and kinematics

    Can anyone define the distinction between the laws of nature and the kinematics of nature? I am thinking that laws have more to do with forces and potentials and kinematics have more to do with velocities and reference frames but I cannot formulate a clear definition of one that does not overlap...
  6. D

    MHB Application of quadratic function in kinematics

    Basically I don't know anyone in real life that can help me with this, so I need help checking to see if my answers are correct :) Part B 1) A golfer hits a nice iron shot and the ball's height above the ground is given by h(t) = -16t^2 + 80t, where t is the time in seconds since the ball was...
  7. G

    Kinematics displacement question

    a man moves in an open field such that after moving 10 m on a straight line he makes a sharp turn of 60 degree to his left .the total displacement after 8 such turns is equal to
  8. M

    Kinematics bouncing ball problem

    given below is a more than one choice type MCQ, A ball is bouncing elastically with a speed 1 m/s between walls of a railway compartment of size 10 m in a direction perpendicular to walls. The train is moving at a constant velocity of 10 m/s parallel to the direction of motion of the ball...
  9. E

    How Does Elevator Motion Affect Work Done by Forces?

    1. Homework Statement the question is: A 62 kg person in an elevator is moving up at a constant speed of 4.0 m/s for 5.0 s. T / I C (b) Calculate the work done by the normal force on the person. (c) Calculate the work done by the force of gravity on the person. (d) How would your...
  10. A

    Relative Velocity, Rigid Body Kinematics

    Homework Statement W(oa) = -5k α(oa) = 3k B = 30 deg B(dot) = -2cos 30i + 2sin30j = Vrel b(double dot) = 4cos30i - 4sin30j) Homework Equations Va = Woa x Rao + Vrel The Attempt at a Solution This is such a simple problem and I don't know why I am messing it up. I am just...
  11. J

    Can the Slower Cyclist Win if the Race is Short Enough?

    Homework Statement Two cyclists are in a race. One cyclist knows that he is slower, so he cheats: he removes the faster cyclist’s bike chain. The cheater starts from rest immediately with acceleration 2.5 m/s2. The faster cyclist has to take 3 seconds to replace her bike chain. She then...
  12. C

    Rocket Kinematics: Acceleration and Maximum Altitude

    Homework Statement You must determine the acceleration of a rocket so that its equipment can be designed to survive. The rocket will have a burn time of t = 30 seconds, during which time it flies has a constant acceleration a. Call this Phase 1. After the fuel is exhausted the rocket enters...
  13. C

    Kinematics: when to use the quadratic formula?

    Hi PF, I'm reviewing my notes from class, starting from the very beginning. I'm working on some problems using kinematic equations. Here's one example: a ball falls from 30m (using down as the positive direction) at a velocity of 8 m/s. how long does it take the ball to hit the ground? Why do I...
  14. H

    Kinematics motion, projectile. This was an mcat problem. Thanks

    A firecracker with mass 100g is propelled vertically with a launch force of 1.2N applied over 5s, after which it explodes into two 50g fragments. One fragment goes horizontally at 15m/s and the other goes to the right at angle 53 degrees with the horizontal at speed 25 m/s. find the distance...
  15. I

    Kinematics Min/Max angles of a projectile

    Homework Statement A football player attempts a 30m field goal. If he is able to impart a velocity u of 30 m/s to the ball,compute the minimum angle θ for which the ball will clear the crossbar of the goal. (Hint: Let m = tanθ .) Homework Equations V0x = V cosθ V0y = V sinθ We get t...
  16. sankalpmittal

    Question regarding kinematics

    Homework Statement There are two rods with one having ring "P" and the other having ring "Q". The rings are connected by a massless and inextensible string which is then connected from "Q" to ceiling. If ring "Q" moves down with velocity "v", what is the velocity of ring "P" ? The string...
  17. H

    Calculate displacement [Two Dimensional Kinematics]

    Homework Statement A skidding car starts moving with a velocity of 6.75m/s at an angle of 58.82657 degrees north of east. Its velocity just before it comes out of its skid 4 seconds later is 3.25 m/s at an angle of 49.6091 degrees south of east. It travels with a constant acceleration while it...
  18. B

    Kinematics of three runners in a race

    Homework Statement Runners A, B, and C run a 100-m race, each at a constant speed. Runner A takes first place, beating runner B by 10 m. Runner B takes second place, beating runner C by 10 m. By what time interval does runner A beat runner C? Homework Equations d = 100 m Δd = 10...
  19. J

    What can stellar kinematics tell us about the IMF?

    How can we use stellar kinematics to measure masses of stars? Any equations or reference papers to explain would be great!
  20. A

    Rollercoaster problem - kinematics & forces

    Homework Statement A small car of mass m is released at height h on a steel track. The car rolls down the track and through a loop of radius R. At the end of the track, the car rolls off the track, which is positioned at a height H above the floor. Neglect friction and the small amount of...
  21. D

    Seemingly simple kinematics exercise

    Homework Statement Rigid body The plane rigid body ABCD shown in the figure has rectangular shape and slides along the orthogonal runners X, Y. The points A and B are always in contact with the ranners. Data: ω=3 rad/s (angular velocity counterclockwise); \Theta=30°; AB=CD=1m; AD=CB=0.5m...
  22. S

    Solving problems in Kinematics with simple calculus

    Hi, I have a generic question about solving kinematic problems using simple calculus. For eg. A variable force F = bv (v is instantaneous speed at some time t) acts on a vehicle moving with speed v. Suppose the initial speed at t = 0 of the vehicle is v0. Calculate the distance through...
  23. M

    Kinematics Problem Homework Help

    1. A car making a 99-km journey travels 38 km/h for the first 49.5 km. How fast must it go during the second 49.5 km to average 47 km/h? 2. Homework Equations ? 3. 47=.5(38+x)
  24. H

    Question related to motion / kinematics

    Homework Statement A bus starts moving with an acceleration of 2m/s^2. a cyclist, 96m behind the bus starts moving towards the bus simultaneously at 20m/s. in how much time will he overtake the bus. Kindly point out the mistake in my solution too. Homework Equations v = u + at s = ut + 1/2...
  25. T

    Planar kinematics of rigid bodies

    Homework Statement Homework Equations I'm dumbfounded by this problem. I can solve the (I think) harder problems with two fixed points and three rod segments. All the examples given in this book are of such "harder" problems and I have absolutely no example that resembles this...
  26. Z

    Relativistic Kinematics conservation of energy

    Homework Statement A particle with rest mass m_{0} and kinetic energy 3m_{0}c^{2} makes a completely inelastic collision with a stationary particle of rest mass 2m_{0}. What are the velocity and rest mass of the composite particle? Homework Equations T = (\gamma - 1)m_{0}c^{2} = E -...
  27. F

    How Does Rotational Momentum Apply in a Combined Linear and Angular System?

    1. Problem statement 2. Related equations I = bmr^2 Energy equations (linear and rotational) 3. Attempt Part a) I know that the distance or height traveled by the box is [h - d] because center of the mass of box is just d. Initial kinetic energy of the box and cylinder is 0 and if only...
  28. A

    Inverse kinematics: Defining a Jacobian of rotation

    I'm working on an inverse kinematics problem (I make video games), and I'm reaching a bit beyond my education. Right now, I've got an algorithm that solves the basic IK equation for a chain of rigid bodies connected by joints by approximately inverting ##J\Delta\theta = e##. Where ##\theta##...
  29. J

    Terminology in rotational kinematics: distance vs displacement

    I'm trying to learn some physics on my own, using the internet as my main source of information. Now, I'm a bit confused about some terminology, and I can't find anything about it... Distance vs displacement in rotational kinematics! Is there a similar difference as in linear kinematics...
  30. S

    1D kinematics - finding g from time traveled

    Homework Statement This is from Kleppner, problem 1.12 in the 2010 edition, if you want to see the diagram. The acceleration of gravity can be measured by projecting a body upward and measuring the time that it takes to pass two given points in both directions. Show that if the time the...
  31. R

    Calculate Acceleration of Falling Hammer on Moon | 1-D Kinematics Problem

    Homework Statement An astronaut standing on a platform on the Moon drops a hammer. If the hammer falls 6.0 meters vertically in 2.7 seconds, what is its acceleration? Homework Equations x=x0+v0t+(1/2)at2 The Attempt at a Solution x=x0+v0t+(1/2)at2 6=0+.5(a)(2.72) 6=3.7a...
  32. A

    Inverse kinematics of manipulators

    Hello, I would like to learn how to calculate and simulate in Matlab inverse kinematics of manipulators.Can you please advise me some good websites or books. I am a beginner. Thanks for any advice.
  33. MarkFL

    MHB Sopheary dara mao's question at Yahoo Answers regarding kinematics

    Here is the question: Here is a link to the question: Calculus Antiderivative problem.? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.
  34. P

    Archived 'Kinematics - Vector Derivative' Exercise

    Homework Statement I'm studying for a Mechanics exam and I have a doubt on a 'Kinematics - Vector Derivative' exercise. I don't know how to begin and that's my main problem. Well, this is the exercise: Some data: This mechanical system comprises: - Body 1: A T-shaped arm, with...
  35. R

    Two Dimensional Kinematics probelms

    Homework Statement 1. At t = 0, a particle leaves the origin with a velocity of 9.0 m/s in the positive y direction and moves in the xy plane with a constant acceleration of (2.0i - 4.0j) m/s2. At the instant the x coordinate of the particle is 15 m, what is the speed of the particle? 2...
  36. M

    Kinematics : A Rock Being Dropped off a Cliff

    Homework Statement A Rock is dropped from a cliff and the sound of it striking the ocean is heard 3 seconds later. If the speed of sound in air is 340m/s, how high is the cliff? Homework Equations The linear kinematics of motion equations: 1. x-x_{0}=v_{0}t+\frac{1}{2}at^2 2...
  37. C

    Calculating Building Height: Quick Kinematics Question

    A stone is dropped from the top of a building. Within the second before it hits the ground, it travels 1/5 of the building's height. Calculate the total height of the building. Been trying to formulate simultaneous equations but there just doesn't seem to be enough information and too many...
  38. D

    How Do You Solve a 1-D Motion Kinematics Problem Involving a Missile?

    Homework Statement A missile is launched into the air at an initial velocity of 80 m/s. It is moving with constant velocity until it reaches 1000m, when the engine fails. a) How long does it take it to reach 1000m b)How high the missile go? c)How long does it take for it to fall back to the...
  39. X

    What is the force of the floor on her feet?

    Homework Statement A 55 kg woman jumps to the floor from a height of 1.5 m. If her body comes to rest during a time interval of 8.00 * 10^-3 seconds, what is the force of the floor on her feet? Homework Equations Unit conversion and g = 9.8m.s^2 ~ 10 m/s^2 The Attempt at a...
  40. C

    Kinematics questions. (Linear & projectile)

    Pictures of the questions are attached below. For question 2, I totally cannot get any answer from the four choices after I substituted everything in the equation. For question 4, I used V^2= U^2 + 2AS, with U being zero, A being 9.8 and S being 2.0. I got C but the answer is D. Can...
  41. C

    Kinematics of a particle with drag

    (this is all in context to a java 2d object and is not homework related) I have an object with velocity v and position x. Its acceleration is directly proportional to velocity squared ie a=k v^{2}. Given the objects initial velocity u and its initial position x_{0} how would i work out its...
  42. J

    Physics Kinematics Homework Help ?

    Physics Kinematics Homework Help!? "While standing on a bridge 18.3 m above the ground, you drop a stone from rest. When the stone has fallen 2.50 m, you throw a second stone straight down. What initial velocity must you give the second stone if they are both to reach the ground at the same...
  43. T

    Kinematics, Newton's Laws, Fun With Engineers

    Homework Statement As a prank, your friends have kidnapped you in your sleep, and transported you out onto the ice covering a local pond. Since you're an engineer, the first thing you do when you wake up is drill a small hole in the ice and estimate the ice to be 6.7cm thick and the distance...
  44. E

    2D Kinematics Problem dealing with acceleration

    Homework Statement " An airplane turns slowly for 9.2s horizontally. The final velocity of the plane is 360km/hr [N]; the average acceleration during the turn is 5.0m/s^2 [W]. What is the initial velocity of the plane?" Homework Equations a=ΔV/t The Attempt at a Solution at=Δv...
  45. A

    Particle Kinematics with Friction

    Homework Statement A 1.5-lb brick is released from rest A and slides down the inclined roof. If the coefficient of friction between the roof and the brick is μ=0.3, determine the speed at which the brick strikes the gutter G. The Attempt at a Solution These are the equations that I got...
  46. A

    Solved: Kinematics Problem: Final Velocity

    Homework Statement A hovercraft is traveling 3m/s at 180 deg. The fan of the hovercraft causes a=4m/s2 at 50° for 10 seconds. Homework Equations What is the final velocity? The Attempt at a Solution v = 3cos180 - 4cos50*10?
  47. M

    MHB Algebra/Physics problem - kinematics

    A light plane must reach a speed of 33 m/s for takeoff. How long must the runway be if the plane has a constant acceleration of 3.8 m/s2 ?so, I am new to kinomatic equations. We are using the 4 Basic ones. need to see this one worked out if I may.Thanks
  48. I

    Kinematics: Slowing Car from 54 to 32 km/h in 65 m

    How long does it take for a car o slow from 54 km/h to 32 km/h over 65 m ?
  49. S

    F = MA 2011 #'s 19, 20 (Force, Kinematics)

    Homework Statement Questions 19 and 20 refer to the following information A particle of mass 2.00 kg moves under a force given by F~ = −(8.00 N/m)(i + j) where i and j are unit vectors in the x and y directions. The particle is placed at the origin with an initial velocity v = (3.00 m/s)i +...
  50. T

    1-d kinematics food fight in space

    Homework Statement Having aced your Physics 2111 class, you get a sweet summer-job working in the International Space Station. Your room-mate, Cosmonaut Valdimir tosses a banana at you at a speed of 14.0 m/s. At exactly the same instant, you fling a scoop of ice cream at Valdimir along...
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