Kinematics Definition and 1000 Threads

Homework Statement Sam is running at 3.8 m/s and is 75m behind John who is running at a constant velocity of 4.2m/s. If Sam accelerates at 0.15m/s^2, how long will it take him to catch John? Homework Equations d = (vf+vi/2)t vf = vi + at d = vit + 1/2at^2 vf^2 = vi^2 + 2ad d = vft -...

Homework Statement A student riding a bicycle begins to go downhill and accelerates at a rate of 1.8m/s2. If the acceleration lasts for 2.4s, and the final speed of the bicycle is 10.2m/s, at what speed was he initially travelling? a = 1.8 t = 2.4 vf = 10.2 vi = ? Homework Equations...

I don't know what to do for these three questions and they're due on Wednesday Homework Statement a. A sprinter can accelerate with constant acceleration for 2.28s before reaching top speed. He can run 148.0m in 16.6s. What is his speed as he crosses the finish line? b. A car...

I'm using a Quantum Physics student textbook for physics at school. My class started with Kinematics and I want to know what pages I should read to better understand the topic.

Homework Statement A man decided to run a marathon. (a) What was his average speed, in m/s, for the first 5K? (b) At 5K, was he speeding up or slowing down? Explain. Homework Equations a) change in distance/time b) acceleration = change in velocity/ change in timeThe Attempt at a Solution...

Homework Statement A pole-vaulter leaves the ground with an upward speed of 9.5 m/s. (a) How fast is she going when she is 2.0 m above the launch point? (b) How long is required to reach this height? (c) Why are there two answers to (b)? The Attempt at a Solution Question A and...

Homework Statement You throw a snowball with an initial speed of 15.0 m/s. Your enemy's head is located 20m away, approximately horizontally. At what angle should you throw the snowball (ignore air resistance)? Homework Equations vf=vi+at d=vit+(1/2)at^2 The Attempt at a Solution

Im sorry I just realized this is in the wrong subforum... Homework Statement Hello Everyone! I am new here and am having trouble with this webassign question. I was able to work out the answer to the first two but the last two are giving me trouble. I am not sure if this is right subforum to...

Hello everyone, I've run across an interesting Newtonian physics problem that I'd like some input on. The problem begins with a rotating object. Let's assume it is a slender rod rotating about one end with a given mass (m), length (L) and rotational speed (ω). This results in the rod having...

Homework Statement A cross country team race is about to begin and team Beta decides to use their one-dimensional kinematics knowledge that they learned from their first year physics course. Each team consists of two people and one horse. The clock is started when the team crosses the...

Homework Statement I know pictures aren't the best, but here it is. Homework Equations The Attempt at a Solution This is my work for this problem. Disregard the drawing as it isn't right. I'm not sure if I'm misinterpreting the horizontal range part or what. I feel pretty...

Kinematics question -- Rocket launch Homework Statement A rocket starts from rest and moves upward from the surface of the earth. For the first 10s of its motion, the vertical acceleration of the rocket is given by ay=(2.70m/s3)t, where the +y-direction is upward. A.What is the height of the...

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...

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...

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

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...

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...

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...

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

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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

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...

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...

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...

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)

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...

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...

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 -...

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...

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##...

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...

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...

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...

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.

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.

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...

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...

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...

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...

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...