The description of the movement of bodies by their position, velocity, acceleration (and possibly higher time derivatives, such as, jerk) without concern for the underlying dynamics/forces/causes.
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1answer
586 views
How do I know an initial speed of a thrown object using the max height [closed]
The simulation being referred to is in box2d
An object is thrown to the max height of $h$ with gravity of $g$, what is it initial speed?
I tried the following:
$v = v_0 - g t$
$0 = v_0 - g t$
$t ...
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votes
1answer
222 views
Calculating the launch angle of a horizontal launch (mechanics) [closed]
I need some help with the following question:
A smooth spherical object (the first object) is projected horizontally from a point of vertical height H = 26.38 metres above horizontal ground with a ...
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1answer
104 views
Simplifying some math for an ant-on-rubber-band problem
OK, I've been doing this problem for fun (it's a great problem, BTW!): http://www.physics.harvard.edu/academics/undergrad/probweek/prob76.pdf
Here is the solution: ...
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votes
2answers
177 views
Why wouldn't this system of equations determine where two balls meet?
A ball is thrown vertically upwards at $5\text{ m/s}$ from a roof top of $100\text{ m}$. The ball B is thrown down from the same point $2\text{ s}$ later at $20\text{ m/s}$. Where and when will ...
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1answer
221 views
Is spherical coordinates enough to calculate the exact position of a point with rotations included?
With "Geographic coordinate system" we only get the location, no rotations or anything. Translated into latitude and longitude.
Where with "Spherical coordinate system", we should be able to get the ...
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1answer
111 views
Find the acceleration based on V² x d graph
How could I find the acceleration of a body knowing only that its position and velocity satisfy $v^2 = f(x)$, where $f(x)$ is a known function of $x$ (position)?
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votes
1answer
460 views
Projectile motion question: vertical and horizontal graph
I've have got some vertical and horizontal distances for a projectile-like motion.
In order to work out the trajectory, why is it better to plot on the x-axis, "horizontal distance^2", and on the y ...
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votes
2answers
423 views
Can someone explain the physics of a standing jump?
I would like to use something like a kinematic equation to know where the person will be in the jump at a given time. However since I think acceleration is not constant because of the jump force it ...
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3answers
242 views
Deccelerate and Accelerate to achieve timed journey
I have a vehicle traveling at initial speed $100\:\mathrm{m/s}$.
Expected destination speed is also $100\:\mathrm{m/s}$.
Maximum deceleration is $3$.
Maximum acceleration is $10$.
Distance to the ...
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0answers
21 views
Functions of time [duplicate]
Following are the functions of time:
$s(t)$ = distance a particle travels from time $0$ to $t$
$v(t)$ = velocity of a particle at time $t$
$a(t)$ = acceleration of a particle at time $t$.
If we want ...
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0answers
26 views
Defining collision point in 3D [closed]
I have a problem with finding collision point of two objects with given speed vectors in 3d. Eg:
...
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3answers
98 views
Solve for Initial Velocity of a projectile given Angle, Gravity, and Initial and Final positions?
I've found equations http://www.physicsclassroom.com/Class/1DKin/U1L6a.cfm for solving everything (and rearranged to solve everything) to do with projectile motion EXCEPT this, even though it should ...
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0answers
34 views
Inelastic relativistic collision [closed]
I have to solve the following problem:
A particle of rest mass, $m_1$, and velocity $v_1$ collides with a stationary particle of mass $m_2$. Find the rest mass $m$ and velocity $v$ of the resultant ...
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0answers
59 views
An unmarked police car passed by a speeding car [closed]
Hi I'm trying to solve the problem
An unmarked police car traveling at a constant speed of 95 km/h is passed by a speeder traveling at 140 km/h. Precisely, 1.00 s after the speeder passes, the ...
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1answer
45 views
Projectile's angle in midflight
For a missile travelling from (0,0) at angle $\theta$ (to the horizontal) and initial velocity $u$, the y (vertical) position at time t is given by
$s_{y} = u\sin (\theta) t - 0.5gt^{2}$
and the x ...
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0answers
53 views
Curvilinear abscissa confusion
How's exactly defined the curvilinear abscissa in kinematics? Surfing on the net I found different definitions:
a) Fixed a point $O$ and a direction, the curvilinear abscissa $s$ at a point $P$ is ...
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0answers
48 views
Driving around a road block? (Quick, turn the wheel !?) [closed]
Consider a car driving with given speed $v$ head-on towards a road block of a certain width.
Car and road block are already so close to each other that a collision would not be avoidable anymore by ...
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0answers
54 views
At an acceleration of 2ft/s^2, how fast could I reach 9.8MPH? [closed]
Question title is self explanatory.
If I'm accelerating at $2ft/s ^{2}$, how long does it take to reach $9.8MPH$?
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0answers
60 views
Magnitude of object's angular acceleration [closed]
I'm studying for a physics exam today and am super stumped on a problem. Would love your help, or some guidance on how to solve it.
An object is being spun at an angular speed of 4.3 rad/s and ...
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0answers
76 views
Physics about plane take off simple find the acceleration problem [closed]
This was on my test, but I kinda botched it I think.
I was trying to use
V^2f = Vo^2 + 2a(delta x)
A plane must reach 226km/h to take off. Runway is 2000m. What's minimum acceleration needed? ...
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2answers
77 views
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0answers
20 views
Movement of a ball on a curved ramp [duplicate]
Possible Duplicate:
What is a natural movement of a ball on a upward curve (the two arrow lines pointing upward) given no external force?
http://i47.tinypic.com/mt55s7.jpg
-See for image
...
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0answers
159 views
Damping force of a shock absorber
I removed a shock absorber from my car, and I have a 50 pound dumbbell, I was gonna hang the dumbbell from the shock absorber and let it drop a known distance to get velocity
From my understanding, ...
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0answers
54 views
Accelerated motions of a car and a truck [closed]
A car and a truck start from rest at the same instant with the car initially at same distance behind the truck. The truck has constant acceleration of 3.4 m/s^2. The car overtakes the truck within the ...
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1answer
272 views
Kinetic energy in the center of mass
In a collision of a particle
of mass $m_1$ moving with speed $v_1$ with a stationary particle
of mass $m_2$ not all the original kinetic energy can be converted
into heat or internal energy. what ...
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0answers
78 views
Physics question motion in two dimensions? [closed]
A ball jumps from the plane and the ball has the acceleraion 500 m/s^2...the ball falls into the ground for 3 seconds..the speed of the plane is 500 m/s headed to east.Determine the position and the ...
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0answers
72 views
Downhill projectile question [closed]
I have to solve the following problem:
A hill is sloped downward at an angle $\theta$ with respect to the horizontal. A projectile of mass $m$ is fired with speed $v_0$ perpendicular to the hill. ...
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0answers
26 views
Intuitive understanding of the equation for kinetic energy [duplicate]
Possible Duplicate:
Why does kinetic energy increase quadratically, not linearly, with speed?
I know this is one of the easiest equations out there and I've used it for years but its still ...
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votes
1answer
68 views
Minimum time required to reach a point [closed]
A police inspecter P is at point $ (\acute{x},\acute{y})$ and a thief X is at point $(x, y)$. X has a constant velocity $V_x\hat{i} + V_y\hat{j} $, where $\hat{i}$ and $\hat{j}$ are unit vectors in ...
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0answers
46 views
Finding an efficient strategy for walking
Let's say you are already walking at a maximally efficient combination of pace and stride (or $\omega$ and $X_0$ I guess) but you need to reach your destination faster. Should you increase/decrease ...
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1answer
181 views
Solving inclined plane using diff. frame
I was trying to solve frictionless inclined plane problem using a diff. frame as shown in the figure, and can't figure out that acceleration along the plane = g.sin(Θ), but I think it should be = ...
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0answers
228 views
Calculating the time given initial position, initial velocity, current position and constant acceleration [closed]
I'm trying to write a simple physics engine (a bit different than what is already out there) and I've got the following problem;
(For simplicity let's imagine this problem in one dimension;)
I have ...
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0answers
492 views
Finding the period and frequency for simple harmonic motion [closed]
A 1 lb weight is suspended from a spring. Let y give the deflection (in inches) of the weight from its static deflection position, where “up” is the positive direction for y. If the static ...
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0answers
150 views
Basic Kinematics Question [closed]
I have a pretty basic problem regarding kinematics, but I'm new to physics. So, I'm having trouble with it. No, it is not homework. These are review problems, but this particular one is troubling me.
...
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0answers
50 views
How to calculate the necessary force to hold a bearing? [closed]
Assume I have a ball bearing which is holding radial load (gravity load) 100lb. The axial rotation has 500 lbf-in. How I can set up the equations to find out the necessary force to hold the bearing to ...
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votes
2answers
278 views
Center of gravity of vehicle and vehicle performance
I am interested to know how does CG of vehicle plays role in the Fuel economy and the vehicle performance. Does CG of vehicle has anything to do while accelerating of your vehicle. I am a student, ...
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0answers
315 views
Velocity using spring contraction
I'm trying to determine the maximum final velocity of a body with which it contracts a spring until it touches the wall. It happens only with the presence of maximum energy. So, I've taken the kinetic ...
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0answers
74 views
Jumping on a landing pad [closed]
I'm trying to make a character jump on a landing pad who stays above him. Here is the formula I've used (everything is pretty much self-explainable, maybe except character_MaxForce that is the total ...
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0answers
104 views
How do I solve this Kinematics question? [closed]
In 1987, Art Boileau won the Los Angeles Marathon, 26 miles and 285 yards, in 2h, 13 minutes and 9 seconds. At the 21-mile mark, Boileau had a 2.50 min lead on the second place winner, who later ...
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0answers
200 views
Projectile Motion
I know the angle at which a projectile is launched, how far it needs to go, and also the maximum height. How can I find the initial velocity needed (disregarding air resistance)?
Currently, I am ...
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0answers
242 views
Basic kinematic equation [closed]
A truck moving with a speed of 18 m/s to a new speed of 13 m/s over a distance of 48 meters. How long did it take for the truck to break to its new speed, and what was the acceleration of the truck?
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0answers
65 views
Kinematics equation [closed]
The motors of an electric train can give it an acceleration of 1 m/ sec square and the brakes can give a negative acceleration 3 metre/ second square. Find shortest time interval in which train can ...
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2answers
160 views
Human Kinematics:Does velocity or acceleration become zero at the moment of changing human limbs' direction of movement?
I need to know the answers to following questions about human kinematics. Can anyone kindly help me with it?
When human moves hand in one direction then suddenly or not changes direction of hand ...
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0answers
389 views
Angle needed to launch a projectile to a given destination at a different height with given initial velocity
I need to calculate the angle required to launch a projectile from point A to point B on an uneven ground, given the parameters.
0nly gravity acts on the projectile – no air resistance.
Parameters ...
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0answers
247 views
Error Analysis, Change in momentum, Kinetic Energy
If momentum of an object is increased by 10%,then its kinetic energy will be increased by?
Well, I don't need the solution logically by calculating the change in Kinetic Energy etc, but my question ...
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0answers
73 views
Does human body parts like hand or leg move with uniform acceleration?
So is this true. I mean does a movement by hand or leg make uniform or constant acceleration?
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0answers
129 views
Meeting Of 2 People On a circular track [closed]
Two persons are running on a circular track either in the same direction or in the opposite direction, indefinitely.
The speed of both of them is given to you.
Speed will be positive in clockwise ...
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votes
3answers
363 views
Finding instantaneous speed in MPH given acceleration, RPM and gear ratio
I am still trying to figure out how to (semi) accurately model instantaneous speed after having found acceleration. I have found that at higher RPMs, the resultant acceleration will be lower. I was ...
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3answers
2k views
Difference b/w Kinetics & Kinematics w/concrete example
(I know whether I understand this or not doesn't matter much to my work & study but am just curious.)
I still can't differentiate in my head kinetics and kinematics (similar thread is found but ...
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1answer
77 views
A Satellite's Perspective
If a planet is spinning east to west and there is a satellite spinning from west to east...
Can the satellite travel at a speed sufficient to make the planet appear, from the vantage point of the ...
