Kinematics Definition and 1000 Threads

Homework Statement A ball starts from rest and rolls down a hill with uniform acceleration, traveling 150 m during the second 5.0 s of its motion. How far did it roll during the first 5.0 s of motion? Vi= 0 at time t=5s -> d= 150 m Homework Equations d=vf+vi/2 * t The Attempt at a...

Homework Statement In Example 2.6, we considered a simple model for a rocket launched from the surface of the Earth. A better expression for a rocket's position measured from the center of the Earth is given by Y(t)=(RE3/2+3(√g/2)REt)2/3 where RE is the radius of the Earth (6.38 ✕ 106 m) and g...

I'm an avid bike rider and a first year physics student. A couple days ago a friend of mine told me about how his friend was going downhill on her bike, used her front brake, and went over. I would like to determine what the minimum speed for a given slope angle is for the biker to do a full...

Homework Statement While standing at the edge of the roof of a building, you throw a stone upward with an initial speed of 6.91 m/s. The stone subsequently falls to the ground, which is 16.5 m below the point where the stone leaves your hand. At what speed does the stone impact the ground? How...

So this question has two parts. The first I got without any trouble: "Two objects move with initial velocity of -8.00 m/s, final velocity of 16.0 m/s, and constant accelerations. (a) The first object has displacement 20.0 m. Find its acceleration." I used The formula Vf2=Vi2+2aΔx and got an...

Homework Statement Ball A is projected vertically upwards at a velocity of 15 m/s from the ground. Ignore the effects of air resistance. One second after Ball A is projected, a second ball B, is thrown vertically downwards at a velocity of 9 m/s from a balcony 30m above the ground. Calculate...

Homework Statement A skier leaves the ramp of a ski jump with V=10.0 m/s at 15° above the horizontal. Slope of mountain below ramp is 50°. Assuming air resistance is negligible, find distance from end of ramp at which skier lands. Homework Equations 1. sf = si + vist + ½ast2 2. tanΘ =...

Homework Statement I have chosen my axis as you can see on the picture. To the left, it is the positive 'r'-axis, up is the positive 'y'-axis. I have to calculate the angular speed. My solution is correct, but I'm getting into trouble at the end. I have to take the roots of the last equation to...

Homework Statement A rock is thrown straight upward from the edge of a 30m cliff, rising 10m, then falling all the way down the base of the cliff.Homework EquationsThe Attempt at a Solution Well, because the rock was thrown 10m up, and then it came all the way down, I added those quantities...

Homework Statement When accelerating upward off a trampoline, how would you depict this on an acceleration-time graph? I know kinematics is the study of motion without a strict regard to the forces that are capable of changing motion, but according to Newton's 2nd law, an object accelerates in...

Homework Statement The human organism can handle acceleration that is 4 times bigger than gravitational acceleration. What is the smallest radius of curvature that can handle pilot of an airplane that files with constant speed of 1000 km/h? Homework Equations This task seems easy but I don't...

Homework Statement A 250 kg box slides down the ramp and then across a level floor. The coefficient of kinetic friction along the floor is 0.20. A person see the box moving at 1.0 m/s(left) and pushes on it with a horizontal force of 140 N (right). How far does the box travel before coming to...

Homework Statement Eliminate t from the equation (x-xi)=vi(t)+1/2(a)t^2 using the kinematic equation v=vi+at to get v^2=vi^2+2a(x-xi) The Attempt at a Solution I wind up with (x-xi)=vi(v-vi/a) + 1/2(v^2-vi^2/a). If the first term on the right side didn't exist, I could see what the solution...

Homework Statement I am stuck with this task please help me. 1. A body is moving with constant deceleration while passing through path that contains two same parts and each one of them is 10m. The first part of the path, body passes for t1= 1s and the second part passes for t2=2.2s. Determine...

Homework Statement Concept Simulation 2.3 provides some background for this problem. A ball is thrown vertically upward, which is the positive direction. A little later it returns to its point of release. The ball is in the air for a total time of 8.21 s. What is its initial velocity? Neglect...

A ball is rolling over a soccer field with constant velocity Vb > 0 at an angle of 45° to the goal line. It starts at the corner of the field (distance d from the middle of the goal line) at the time t0 = 0. At the same time a player starts heading towards the goal on a path perpendicular to the...

Homework Statement A train that runs 140 km / h requires about 700m to stop. Calculate the average acceleration of the train while braking.Homework Equations v: x/t[/B]The Attempt at a Solution v= x/t so t= x/v= 700m/ (38.89m/s)=18 s Now to find acceleration a= v/t a= 38,89m/s / 18s =2,160...

Homework Statement A sled starts from rest and slides down an inclined plane with constant acceleration. In three seconds, it has traveled 9m. How long does it take to reach a velocity of 24m / s? Homework Equations d = vi * t + ½ * a * t^2, vi = 0[/B] vf = vi + a * t, vi = 0 The Attempt...

13) A golfer hits a ball at 100 m/s with an angle of elevation of 30 degrees towards a green. The acceleration due to gravity is 9.8 m/s^2 [down]. There is no resistance. a) If the green is at the same height as the golfer then find how long the ball is in the air, and how far away the ball...

Homework Statement Homework EquationsThe Attempt at a Solution First, I find the accelerations of each block, separate the accelerations into Y and X components and then add them as vectors. for B: B goes down the ramp with an acceleration of 3.35 m/s^2 X component : (3.35)(cos 20) = 3.15...

Homework Statement Homework EquationsThe Attempt at a Solution When the barrel starts to tip, the normal at point A should be 0 Newtons, and then all weight would be on point B. I'm guessing if the barrel would tip, it wouldn't be sliding across the floor so kinetic friction is not used...

Homework Statement The wheel shown rotates about point O. Point A has a velocity=-7j in/sec. Point B has a tangential velocity=-4i in/sec^2 Determine the absolute acceleration of Point C located on the circle. radius=6 in You will have to look at the figure for more clarification please...

Homework Statement Refer to figure please. Homework Equations ∑Fy=0 before string is cut The Attempt at a Solution I tried summing the two forces in the y direction before the strings were cut which would be the two tensions at a sin40° and minus the weight of the ball(mg). That gave me T in...

Homework Statement A stone is dropped in a well. The splash is heard 3s later. What is the depth of the well? Homework Equations constant acceleration equations take speed of sound to be 343 m/s. The Attempt at a Solution For the stone: u = 0 a = g s = ut + 0.5at^2 subbing it all in you get...

[You don't need to read the whole thing, but I'd recommend doing so, because there are examples of my struggles somewhere in there, like specific problems.] Greetings as usual, It's me again. That hopeful physicist who somehow found himself at the wrong place with the wrong mind in the wrong...

Homework Statement For the first half of a straightly traveled path which is α=60° from some reference line, a body is moving with a velocity of v1=72 km/h. During the second half of a straightly traveled path, the body is moving with an angle of β=30° with a velocity of v2=36 km/h.What is the...

Well, the problem says: From some height a object with mass m is thrown . Determinate the law that describes how the velocity of fall v changes, if on the object, besides gravity, acts the force air resistance, which is proportional to velocity v (the proportionality coefficient is k), ie must...

Homework Statement Hello there, I have answered the first part by calculating the retarden force is equal to 80*cos30. This gave me an answer of 69.3N. I was wondering if someone could point me in the right direction to ascertain the force needed to accelerate the mass by 1ms-2 along the...

wrobel submitted a new PF Insights post Basics Kinematics Continue reading the Original PF Insights Post.

1. http://www.physicsclassroom.com/Class/1DKin/U1L3a16.gif 2. http://www.physicsclassroom.com/Class/1DKin/U1L3a17.GIF In the first graph, I get that that the slope is negative and that the object is speeding up And in the second graph, the slope is negative and the object is slowing down But...

Homework Statement A boat is crossing a river between via points A and B which are d=400m apart. The speed of the river is V2=2 m/s and is constant along the AB line. The angle of the boats trajectory is α=45 degrees. At what speed V2 and with what angle β should the boat be directed so that it...

Homework Statement Two bodies are moving on the same line. When they move away from each other the distance between them changes for 16m in a time interval of 3 s (Δd1 = 16 m ; Δt1 = 3 s). When they move towards each other the distance between them changes for 3 m in a time interval of 3 s (Δd2...

I am having a great difficulty in plotting, understanding & visualising the graphs, which is important aspect in physics. So I want some help from everyone to please show me, how to understand a given graph better & juice out everything which it wants. I want to make my fundamental strong by...

Homework Statement A person decides to swim across a river 84m wide that has a current moving with a velocity of 0.40m/s[E]. The person swims 0.70m/s[N] relative to the water. In what direction should she swim if she lands at a point directly north of her starting position? Note: This is part...

Homework Statement A particle moves along a straight line so that its acceleration t seconds after passing a fixed point O on the line is (2 - 2t) cm/s2. Three seconds after passing O, the particle has a velocity of 5 cm/s. Find and expression, in terms of t, for the velocity of the particle...

Homework Statement Two football players separated by 42m run directly toward each other. Football player 1 starts from rest and accelerates at 2.4m/s^2, and football player 2 moves uniformly at 5.4m/s. How long does it take for the players to collide? Given: player 1: v1=0m/s, a=2.4m/s^2Player...

wrobel submitted a new PF Insights post Rare Kinematic Formula Continue reading the Original PF Insights Post.

Homework Statement Humpty Dumpty had a great fall from a roof. It took him 2.25s to fall. How high was the roof? Homework EquationsThe Attempt at a Solution

Homework Statement Homework Equations i) F=ma=mv/t ii) E=mv2/2 The Attempt at a Solution Now based on equation 1 , I have concluded that the velocity gained is inversely proportional to m, and that so is the kinetic energy , I have seen otherwise.[/B]

Homework Statement A police car at rest, is passed by a speeder traveling at constant speed of 180 km/hr, take off in hot pursuit accelerating at 3.7 m/s². How far has the police car traveled to catch the speeder? Homework Equations I think we would use x = xo + vot + 1/2at^2[/B] (Or maybe...

Homework Statement A wheel of diameter 45.0 cm starts from rest and rotates with a constant angular acceleration of 2.50 rad/s2 . At the instant the wheel has completed its second revolution, compute the radial acceleration of a point on the rim in two ways. 1 Using the relationship...

Homework Statement A bomb is dropped from an airplane at an attitude of 14400 ft. The plane is moving at 600 miles per hour. How far will the bomb move horizontally after it is released from the plane? Homework Equations I use the formula involving the distance traveled by an object with no...

Referring to slides 3-4 (page 2) of this link: https://www.princeton.edu/~stengel/MAE331Lecture9.pdf The author states the relationship between body rates [p q r] and Euler angle rates [φ_dot θ_dot ψ_dot]. I want to verify this but have been failing miserably... My reasoning: 1) p, q, and r...

Homework Statement The rod OA rotates clockwise with a constant angular velocity of 6 rad/s. Two pin-connected slider blocks located at B move freely on OA and the curved rod whose shape is a limacon described by the equation r = 200*(2-cosθ) mm. Determine the magnitude of the acceleration of...

Homework Statement [/B] find the period with only using L (for the long of the rope), R (for the radius), M (for the mass), and G (for the gravity) Homework Equations V=ωR Fcentripetal = ##\frac {MV^2} {R}## Fgravity = MG phytagoras basic trigonometry The Attempt at a Solution [/B] i have...

Homework Statement Car A is traveling a distance d behind Car B. Initically both cars are traveling at the same speed of 60 ft/s. Suddenly Car B applies the brakes, causing Car B to decelerate at 8ft/s2. It takes the driver of Car A 0.75 seconds to react, and when she applies her brakes Car A...

Does anyone have suggestions on the strategies for a four-body decay's kinematics? I'm just wondering what is out there. Last time I had to calculate something I just did it straightforward, but I know there must be other methods. (Like preferring to work in energies over invariants). I usually...

Homework Statement An object is moving in the xy-plane according to the equations x(t) = 3sin(3t) and y(t) = 4cos(3t). What is the maximum magnitude of the particle's acceleration? 1) 5 m/s22) 15 m/s23) 30 m/s24) 36 m/s2 [the accepted answer]5) 45 m/s2 Homework Equations x(t) =...

Homework Statement bicyclist increases its velocity at constant power a) how great is this power when the bicycle's velocity increases, from 18km/h to 23km/h, during the time of 1,2 seconds b) Within which boundaries does the acceleration vary? The combined mass of bicyclist and his bicycle...

Homework Statement The performance of a car is being tested. Distance driven is 400m. The car accelerates from a standing start (v0 = 0). (reader's note: It could be plausibly assumed that car performance tests are measured at even ground.) The car's mass is 1150kg. The time taken in the...