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.
2
votes
12answers
3k views
List of good classical physics books
What are some good books for learning the concepts of Kinematics, Newton laws, 2D Motion of Object etc.?
37
votes
14answers
7k views
Why does kinetic energy increase quadratically, not linearly, with speed?
As Wikipedia says:
[...] the kinetic energy of a non-rotating object of mass $m$ traveling at a speed $v$ is $mv^2/2$.
Why does this not increase linearly with speed? Why does it take so much ...
6
votes
2answers
785 views
Physics of simple collisions
I'm building a physics simulator for a graphics course, and so far I have it implementing gravitational and Coulomb forces. I want to add collisions next, but I'm not exactly sure how to go about ...
2
votes
2answers
180 views
How do I adjust the kinematic equations to avoid reaching speeds faster than light?
I like some 'science' in my 'science fiction', so I started crunching out the kinematic equations for some of the scenarios my characters are getting involved in, and ran smack dab into an issue. ...
7
votes
5answers
533 views
Should you run when under rain?
When it's raining, would you get less wet if you run or more wet?
I think you will get less wet, because rain is coming down in a constant volume and if you run you will have a shorter amount of time ...
0
votes
2answers
464 views
What will be the relative speed of the fly? [duplicate]
It has happened many times and i have ignored it everytime.
Yesterday it happened again .
I was travelling in a train and saw a fly (insect) flying near my seat.
Train was running at a speed of ...
8
votes
3answers
1k views
Can superconducting magnets fly (or repel the earth's core)?
If a superconducting magnet and appropriate power supply had just enough $I\cdot s$ (current $\cdot$ length) so that when it was perpendicular to the earth's magnetic field, the force of the ...
1
vote
2answers
218 views
Doubt concerning centripetal acceleration
What is the centripetal acceleration and angular velocity of a child located 8.2 m
the center of a carousel? The speed (size of the tangential velocity) of the child is
2.1 m / s
A train moves in a ...
3
votes
2answers
218 views
The Double Integrator: Matching velocity and position as quickly as possible with only a limited amount of force available
If a body with mass $m$ begins at position $x_0$ with velocity $v_0$ and experiences a force that varies as a function of time $f(t)$ (and we ignore gravity, friction, and everything else that might ...
2
votes
1answer
11k views
Solving for initial velocity required to launch a projectile to a given destination at a different height
I need to calculate the initial velocity required to launch a projectile at a given angle from point A to point B. The only force acting on the projectile after launch will be gravity – zero air ...
2
votes
1answer
129 views
Is it possible to rotate an angle on perfectly smooth ice?
You must start and end with the same pose.
Prove it if you think you can't.
1
vote
2answers
124 views
Functions of Time
1) Is position a function of time only or also velocity? Likewise, is velocity a function of time only or also the position?
2) The following are functions of time:
$s(t)$ = distance a particle ...
1
vote
1answer
696 views
Trajectory of projectile thrown downhill
I'm teaching myself mechanics, and set out to solve a problem determining the optimum angle to throw a projectile when standing on a hill, for maximum range. My answer seems almost plausible, except ...
0
votes
3answers
585 views
Very basic question: When to use $s=vt$, $s=1/2vt$, $s=at$ and $s=a/t^2$?
Very basic question: When to use $s=vt$, $s=\frac{1}{2}vt$, $s=at$ and $s=\frac{a}{t^2}$?
What was the difference between those?
14
votes
10answers
12k views
What is the difference between “kinematics” and “dynamics”?
I have noticed that authors in the literature sometimes divide characteristics of some phenomenon into "kinematics" and "dynamics".
I first encountered this in Jackson's E&M book, where, in ...
6
votes
4answers
123 views
Integrating radial free fall in Newtonian gravity
I thought this would be a simple question, but I'm having trouble figuring it out. Not a homework assignment btw. I am a physics student and am just genuinely interested in physics problems involving ...
3
votes
2answers
277 views
Galilean invariance of the Schrodinger equation
I am only asking this question so that I can write an answer myself with the content found here:
http://en.wikipedia.org/wiki/User:Likebox/Schrodinger#Galilean_invariance
and here:
...
14
votes
6answers
3k views
Is two cars colliding at 50mph the same as one car colliding into a wall at 100 mph?
I was watching a youtube video the other day where an economist said that he challenged his physics professor on this question back when he was in school. His professor said each scenario is the same, ...
3
votes
2answers
960 views
Formulas for ball rolling in a bowl?
I'm developing a program where I've a ball/sphere rolling in a bowl from the side at top, till the center at bottom, and I'm trying to get the formulas for:
The rotation angle and the position of ...
4
votes
5answers
4k views
Distance when acceleration not constant
I have a background in calculus but don't really know anything about physics. Forgive me if this is a really basic question.
The equation for distance of an accelerating object with constant ...
3
votes
3answers
3k views
Ion Drive Propulsion Top Speed
I would like to know if there is some formula / graph which would provide / show the efficiency of a certain type of propeller in space. Specifically, I'm interested in the acceleration attainable at ...
3
votes
2answers
676 views
Is there a 2D generalization of the coefficient of restitution?
The coefficient of restitution characterizes a collision in one dimension by relating the initial and final speeds of the particles involved,
$$C_R = -\frac{v_{2f} - v_{1f}}{v_{2i} - v_{1i}}$$
In a ...
2
votes
2answers
315 views
How to calculate a firing location from point of impact data?
I would like to know how to calculate the point at which a bullet is fired from a gun given information from the scene where the bullet falls. The scene would contain the point of impact (GPS ...
2
votes
8answers
1k views
Real world examples for projectile thrown upwards or downwards
I am preparing a physics course for high school about projectile motions. If a projectile moves with initial velocity $v_0$ in the gravitational field of the earth, the equation
$$
s(t) = 1/2 g t^2 ...
1
vote
2answers
214 views
Using acceleration to plot position
Sorry if this question is dumb, and I know is physics 101, but I'm not that good with physics.
I'm writing an iPhone program that by collecting the acceleration data of the device tries to replicate ...
0
votes
2answers
382 views
Does an airplane's speed include the speed of the Earth?
After take off, does airplane's speed include Earth's movement/speed? Do airplanes turn with Earth movement/rotation?
6
votes
5answers
8k views
How to calculate average speed
I recently encountered a puzzle where a person drove 120 miles at 40mph, then drove back the same 120 miles at 60mph. The average of the speeds is (40mph+60mph)/2 = 50mph, so the total trip time ...
3
votes
1answer
161 views
Lab observation correct? As distance decreases, velocity increases, stderr decreases
The experiment goes like this:
Allow a moving cart to move from the top of an incline plane ($x_0$) downwards. The time taken will be recorded by the picket fence (those things you see wired up). ...
2
votes
1answer
462 views
Determine acceleration from experiment (Newton 2nd Law)
I have done a physics experiment (setup below). And was asked to determine the experimental and theoretical acceleration.
The data I've got
Ok, am I right to say
Experimental acceleration ...
2
votes
2answers
195 views
What is the displacement of an accelerated and relativistic object?
Displacement in an accelerated classical object is:
$$s=ut+\frac {at^2}{2}$$
What is the displacement of an accelerated relativistic object?
In Newtonian mechanics there are two types of ...
2
votes
2answers
3k views
Difference between momentum and kinetic energy
From a mathematical point of view it seems to be clear what's the difference between momentum and $mv$ and kinetic energy $\frac{1}{2} m v^2$. Now my problem is the following: Suppose you want to ...
1
vote
1answer
543 views
Newton 2nd Law: Does vertical force (mass) affect the horizontal acceleration?
I learnt before that if 2 forces are perpendicular to each other, they should not affect each other. However in a recent experiment setup (asked in another question):
I believe the theoratical ...
1
vote
2answers
380 views
2d simulation shooting projectiles that inherit the gun's veocity at a moving target while also moving
Overview: I'm working on programming a simulation that requires 'shooting' projectile-type objects at other moving objects. How can I calculate the angle at which to shoot the object to hit?
Details:
...
1
vote
2answers
215 views
Running: Determine how much more energy is needed per extra kilogram of weight
(I recently asked this on maths but was directed here)
I have recently become a runner and having a keen interest in kinematics I'm very interested in the maths/physics of my running.
Can someone ...
0
votes
2answers
719 views
Preventing a block from sliding on a frictionless inclined plane
I want to demonstrate what force $F$ you would have to exert on an inclined plane of angle $t$, mass $M$ to prevent a block on top of it with mass $m$ from sliding up or down the ramp. I worked out ...
0
votes
2answers
340 views
Finding Distance an Object Travels Up an Incline After Launch
I've been doing a review for an introductory physics course final. I have a question on one problem though. Here is the problem:
A mass (M=2kg) is placed in front of a spring with k=900N/m,
...
0
votes
2answers
659 views
Position in circular motion
Is it possible to determine the position of a particle undergoing circular motion, in x-y coordinates, at any given time and velocity?
I'm thinking it has something to do with $\pi$
