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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3answers
763 views

Calculate kinematics of body movement from the set of spatial coordinates

Short intro I have a set of 3D (x,y,z) spatial coordinates of arm movement obtained using motion capture system. The example set of such coordinates looks like this (rounded up): ...
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1answer
87 views

What are the equations for motion with constant jerk?

Every one knows the three famous equations for motions with constant acceleration . But what if the motion were having a jerk? How should then be the equations for motions? How can I find them?
5
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2answers
96 views

How long does it take to optimally change position and velocity?

A spaceship moving in two dimensions is at position $(x, y)$ and has a velocity $(v_x, v_y)$. It also has a maximum acceleration $a_{max}$. Its goal is to be at position $(x', y')$ with a velocity of ...
2
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0answers
41 views

2d particle collision, Time for one particle to catch another one [duplicate]

Say we have 2 particles where 1 moves with constant velocity $u$ and the other moves with speed $v$ towards the first particle. After what time does the 2nd particle catches up with the 1st one?
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2answers
120 views

What is the relation between kinetic energy and momentum? [closed]

If kinetic energy is doubled, what happens to momentum? Is it also doubled? I've tried working through the formulas for each but keep getting lost. $$KE=\frac{mv^2}{2}$$ $$p=mv$$ so if ...
2
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2answers
53 views

Why should $\langle xf_r\rangle=0$ but $\langle\dot{x}f_r\rangle\ne 0$?

All the $\langle\rangle$ in this question is the mean value theorem over a large number of experiments. Consider a Brownian particle moving in a liquid with the viscosity $\mu$. The equation of ...
9
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4answers
4k views

Why does a ball bounce lower?

If a ball hits the floor after an acceleration then why does it bounces lower? I mean the Energy is passed to the floor then why does the floor give back less Energy?
0
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1answer
46 views

Questions about basic jump physics

This is a problem a friend and I are working on for an undergrad reading course. Our goal at the end is to make an accurate two-dimensional model of the human jump using Processing by the end of next ...
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2answers
85 views

Converting velocity-time line to acceleration-time?

How would one find where the straight line on a VT graph is on an AT graph? For example in the above image, if I were to convert that into an acceleration-time graph, where on the y-axis would the ...
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2answers
5k views
0
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0answers
22 views

Question on using Transport Theorem to Determine Angular Acceleration of a Rotating Frame

My question is regarding using the "Transport Theorem" on the angular-velocity vector of a rotating frame itself. Suppose: Frame-F has basis vectors I, J, K. Frame B is rotating with respect to F ...
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3answers
111 views

Calculate average speed of projectile with air resistance

There's a project that I'm working on that been bugging me for awhile. The project involves this senario: A projectile is released at 1000 feet per second and moves in a straight line infinitely ...
3
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2answers
147 views

Why and when do we differentiate or integrate equations in physics? [closed]

I'm an engineering student and none of my professors ever explained why do we use derivations and/or integrations in physics. So I have this task, it goes like: The object is moving in a positive ...
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1answer
29 views

energy, gravity and buoyancy working together

What will happen to the objects in this youtube video? https://www.youtube.com/watch?v=c5FF6DEaXTw
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0answers
17 views

Finding final velocity of neutron [closed]

A neutron moves with velocity $u$. It collides head-on with a stationary nitrogen nucleus. The collision is elastic. The mass of a nitrogen nucleus is 14 times that of a neutron. After collision ...
0
votes
1answer
27 views

two bodies are travelling with equal acceleration

two bodies are travelling with equal acceleration in the same direction and are in contact with each other. What will the force exerted by 1st body on second be? By taking an example of masses 5 and ...
2
votes
3answers
106 views

Calculating vector to aim for moving asteroid (3D asteroid game)

Considering we're in a 3D system of coordinates: our ship is at point A, motionless our ship can shoot bullets, the speed of which is known the asteroid is at point B the asteroid is moving on known ...
0
votes
1answer
50 views

Power - 1/2 Force x velocity? [closed]

A pump, taking water from a large reservoir, is used to spray a jet of water with speed 20m/s. The nozzle of the pipe has radius 0.05m, and is level with the surface of the reservoir (no change in ...
0
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1answer
24 views

Direction of the particle's motion

^ y | | |--------------> x Above I have labelled the axes of the graph. In the figure we can see that the direction of the particles motion is downward ...
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4answers
96 views

Why do two formulas $d = v_0 t + \frac{at^2}{2}$ and $d=vt$ yield different results?

All of you are sure to be familiar with these two equation: $d = v_0 t + \frac{at^2}{2}$ and $d=\overline vt$ Given the same initial and final velocities, and time and acceleration. With the ...
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2answers
58 views

A question regarding 3 bodies connected as a system

Let us consider three bodies of equal mass connected to each other with 2 ideal strings of length l. The three bodies are placed in a straight line In this arrangement there is 1 body connected to 2 ...
2
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2answers
61 views

Determining Acceleration Based On Graph

I understand how to solve this problem, but I am unsure how to generate an equation for the graph (below). My current attempt involves using the mass provided along with the derivative of the line ...
0
votes
1answer
37 views

A question on a body moving up a ramp [closed]

Let us consider a ramp of vertical height $h$ and an angle $x$. A body at the bottom of the ramp is given a velocity $v$ such that it moves up the ramp length and continues as a body that is ...
11
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3answers
954 views

Center-of-mass frame for massless particles

Given a scattering event where a photon and electron go in and a photon and electron come out, what is the center of mass frame? I'd say, since the photon has no mass, it's the rest frame of the ...
1
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0answers
50 views

Projectile motion, solved with perturbation theory [closed]

A ball is dropped from rest, the initial height is $h_1$. There is air resistance given by $-mkv$. In the downward motion, the equation of motion can by written as $$\dot v = -g-kv$$ with the y ...
0
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1answer
52 views

Tangential velocity of a parabola

For an experiment on the parabola motus we decided to calculate the velocity of the object thrown in three phases: When the object leaves the spring that throws it (we solved it using conservation ...
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2answers
51 views

Finding the initial velocity of a vertical circular motion [closed]

A particle P is suspended from a fixed point O by a light inextensible string of length a. When hanging at rest under gravity at A it is given a horizontal velocity u. The particle moves freely ...
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0answers
22 views

Recommend books on mechanics, motion and it's laws [duplicate]

I want a book that discuss all these things practically. I don't require it for any exam. Just for applying it confidently anywhere (want to Analyse fluids,thermo etc.) Want a book that explain how to ...
1
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1answer
28 views

Speed with wind resistance

This is probably a basic question, but it has been a while since I did anything like this. If a boat is sailing forward at speed $x$ and the direction of the wind, with magnitude $y$, is either equal, ...
1
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1answer
50 views

What does it mean by $t=-1$?

if the position vector of a particle is $\hat{r}=\left(4+3t\right)\hat{\imath}+\left(t^3\right)\hat{\jmath}+\left(-5t\right)\hat{k}$, i want to find at what time this particle passes through the point ...
1
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1answer
44 views

Problem with formula for parabolic motus

I know that the path made by an object thrown in air with velocity $v_0$ with an angle $\alpha$ is: $$y=x \cdot\tan \alpha - \frac {gx^2}{2v_0^2\cdot \cos^2 \alpha} $$ At school we had to use this ...
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votes
1answer
39 views

How to define the dilatation rate (strain) between two particles knowing the instantaneous positions and velocities?

Provided that I have the instantaneous positions and velocities of two particles that can separate in 3D with respect to time. I would like to characterize the change in length. What could be a good ...
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votes
3answers
115 views

Question on acceleration of gravity

In pre-calculus last week my teacher explained a scenario in which a man throws a rock down a well and takes 4 seconds for you to hear the rock hit the bottom. How far downs the well? Last years I ...
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2answers
92 views

What is the percentage of energy recovery in Kinetic Energy Recovery Systems(KERS) in cars?

Kinetic Energy Recovery Systems (KERS) use flywheels to recover energy from the kinetic motion of cars. They use a rotating flywheel that generates energy as it rotates- this generates the electric ...
0
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1answer
45 views

Kinematics Word Problem [closed]

A curling rink is approximately 35 m long from button to button. Mr. Grover releases a rock and 20. seconds later it stops on the far button. What was the initial velocity of the stone? What ...
0
votes
4answers
424 views

When does acceleration due to gravity equal positive/negative? [closed]

For example a projectile is launched at an angle. What would $a$ in $y=vt +.5at^2$ be? Let's say I choose up to be positive. How do you not confuse yourself whether to use positive or negative $a$?
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1answer
192 views

Gas viscosity at high pressure, high temperature

EDIT 1 PER COMMENTS I am wanting to model nitrogen gas viscosity as a function of pressure and temperature OR learn of an existing equation that models nitrogen viscosity for the pressure and ...
3
votes
1answer
67 views

Non-deterministic particle system

This question is in the spirit of Norton's dome, an example of an apparently non-deterministic system in Newtonian mechanics. Under certain restrictions, the Picard–Lindelöf theorem guarantees the ...
0
votes
2answers
43 views

Orientation of a rocket going in a circle?

This problem is from my physics homework: A rocket is moving at constant speed in a perfect circle in deep space, far away from any planets or stars. The diagram below shows the circle the ship ...
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2answers
61 views

Finding the point of passing between two objects of different velocities

Let's say an there are two objects or vehicles, both of them travel towards the same direction with constant velocities, the other object being slower than the other. How do you calculate at which ...
5
votes
5answers
945 views

How does an object's motion behave if dropped from an aeroplane travelling diagonally upwards?

Imagine an aeroplane travelling with velocity $v$ at some angle $\alpha$ from East to North. A box is dropped from the aeroplane. What would the projectile of the box be? Would it be a parabola with ...
1
vote
1answer
35 views

Instantaneous velocity is slope of displacement-time curve?

I have a toss-up question that I'm not sure how to answer. Here it is (true or false): The instantaneous velocity at a particular time is the slope of the displacement-time curve at that position. ...
0
votes
1answer
29 views

Confusion about horizonally projected body

DESCRIBED IN IMAGE CLEARLY In the text book, I got the initial velocity of x-component initial velocity Vxi, Vxi = Vi cos(0); (0 = zero) but what if it is like the picture i showed, first it was ...
0
votes
1answer
68 views

Calculating force of a car [closed]

I'm simulating car cruise system and my results are not making any sense. I have been told that my force formula is wrong but I don’t understand why it is wrong and how I can fix this. Does anybody ...
1
vote
2answers
160 views

Quick question on free fall of 2 objects [closed]

I am trying to work through a problem, that is basically telling me that two objects were dropped from a building, one was thrown 2 seconds after the previous object, and I have to find out how long ...
1
vote
3answers
6k views

Stopping Distance (frictionless)

Assuming I have a body travelling in space at a rate of $1000~\text{m/s}$. Let's also assume my maximum deceleration speed is $10~\text{m/s}^2$. How can I calculate the minimum stopping distance of ...
0
votes
2answers
38 views

How do I make an equation to be dimensionally consistent? [closed]

Velocity is related to acceleration and distance by the following expression: $$v^2=2ax^P$$ Find the power P that makes this equation dimensionally consistent. $$\frac{v^2}{2a}=x^P$$ ...
0
votes
1answer
109 views

Frictionless Cart on a Ramp (Experimental Design Question)

Question: Why is the calculated value for our final velocity higher than our predicted value? Since our prediction neglected air resistance and friction, shouldn't the velocity for the actual cart ...
0
votes
0answers
24 views

How to find the function of acceleration respect to time while having the function of acceleration with respect to velocity [duplicate]

As everyone know that the integral of acceleration respect to time will give the function of velocity respect to time. However, my question concern the different case when the function of a(t) is not ...
1
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2answers
29 views

What acceleration to use in this problem?

A balloon starts rising from the ground with an acceleration of 1.25 m/second square. After 8 second, a stone is released from the balloon. Find the time for stone to reach ground, distance ...