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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2answers
620 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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1answer
206 views

Proving $t=(1+\sqrt{1+2hg/v^2 } ) (v/g)$ for a thrown ball [closed]

If we throw a ball from the hight point $h$ from the earth, with initial velocity $v’$, how to prove that the time it takes the ball to reach the earth is given by: ...
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1answer
3k views

Calculation of Distance from measured Acceleration vs Time

I have an Accelerometer connected to a device that feeds the instant values of the acceleration in the 3 directions. I've tried to calculate the distance for a vertical movement using these values ...
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2answers
483 views

Closest model for relationship between velocity and distance

Which is the model that best shows the relationship between velocity and distance: $v \propto d$ $v \propto d^2$ $v^2 \propto d$ $v^2 \propto d^2$ What I think is from: $$v=at \Rightarrow ...
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1answer
84 views

Vehicle acceleration

What I'm essentially doing is Kalman Filter. If anyone is familiar with (but it doesn't really matter in this case). Consider the following formulas: $$x_k=x_{k-1}+v_{k-1}dt+a_{k-1}\frac{dt^2}{2}$$ ...
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1answer
457 views

End position of movement factoring in deceleration

Ok I am hoping to apply this answer to a piece of software, but it uses physics to work out the result so I require some help in that department. I will attempt to explain this the best I can. I ...
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2answers
551 views

Time and distance where velocity is a function of time

I'm creating a video game set in space in which spaceships travelling between places accelerate until they hit a maximum velocity. They then travel at that velocity until a time when they need to ...
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3answers
974 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?
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1answer
669 views

How do I determine a component of relative velocity?

At a particular instant, a stationary observer on the ground sees a package falling with speed v1 at an angle to the vertical. To a pilot flying horizontally at constant speed relative to the ...
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3answers
935 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, ...
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2answers
644 views

Does acceleration at an angle to velocity change the direction?

During an interval of time, a tennis ball is moved so that the angle between the velocity and the acceleration of the ball is kept at a constant 120º. Which statement is true about the tennis ball ...
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2answers
2k 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 $\pi$
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1answer
188 views

Kinematics of scratching a rolling tire

Recently a "U" shaped scratch appeared on my car's front tire. It looks like someone rolled past a curb and scraped it. This has led me to the following problem: Generate a plot (ideally polar) of a ...
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1answer
39 views

Calculating force of a car [on hold]

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 ...
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1answer
20 views

hydraulic scissor jack lifting capacity

Can you please assist with a really simple question? I have a hydraulic scissor jack table with the following: 2 hydraulic cylinders, each with a cylinder stroke of 240mm, a cylinder bore of 50mm ...
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1answer
42 views

Interaction of solid objects and change of trajectory

I have two solid objects. Each of them has an arbitary complex surface, which is discribed by set of vertices. The aim is to describe their interaction, result of which is the change in trajectory of ...
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1answer
191 views

What strategy should I use to approach this problem? If my straight line approximation doesn't work [on hold]

recently i wrote an assignment in one of the questions i got two different answers for the same question by considering a straight line motion The question was somewhat like this THIS IS A HOMEWORK ...
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1answer
16 views

Elementary question about velocity

When we talk about the nonvanishing velocity of an object, are we assuming we are static relative to the object or not?
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2answers
42 views

Finding out the velocity [closed]

Displacement of an object is related to time $x=at+bt^2-ct^3$ where a, b and c are constant motion.Then the velocity of an object when it's acceleration is zero is given by ...
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2answers
52 views

When solving kinematics questions, how to find time in air?

I was trying to help a friend with this question: A ball is shot horizontally off a cliff. What would happen to the horizontal distance it travels if the acceleration due to gravity were doubled ...
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1answer
34 views

Compute the minimal distance between two points in movement

There are two points, $A$ and $B$ that move according to these laws: $$ \vec{x_a}= 20 -10 t $$ $$ \vec{x_b}= -15 +15 t $$ $A$ moves along the x axis, $B$ along the y axis. I have to compute the ...
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1answer
47 views

Two equations for $y$ in projectile motions

I have two equations on my equation sheet: $$y=v_o t \sin \theta - \frac{1}{2} g t^2.$$ And then another: $$y_{\max} = \frac{v_o^2 \sin 2 \theta }{2g}.$$ I understand that the first one is an ...
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1answer
75 views

Small Animal Terminal Velocity

I recently saw a cat fall probably 100 feet like in this video Cat Falls. It seemed as if the cat reached terminal velocity by the time it hit. Does this mean that cats (and other small animals) could ...
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1answer
67 views

Is it possible to work out the shortest time in which a body can travel a certain distance if all that is provided is the max a, max -a, v1, v2 and s?

Is it possible to calculate the shortest time it takes a body to travel a certain distance if the only information provided is its maximum acceleration, its maximum retardation and the distance it ...
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1answer
41 views

A pearl that moves in a smooth vertical hoop

I wanted to ask about the situation of a pearl that moves in a smooth vertical hoop in circular motion as described in the following sketch. According to a simulation found in the internet , a ...
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2answers
55 views

Motion of two gravitational bodies?

I'm doing a basic realtime simulation of two bodies, but the orbits are unstable for some reason. This code is run at every timestep: ...
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1answer
43 views

Streamlines for steady flow problem

I need to calculate the streamlines for the steady flow given by the velocity field $$\mathbf{u}=(u,v,w) = \left( 0,\frac{y}{y^2 +z^2} , \frac{z}{y^2 +z^2}\right)$$ Now I've been able to notice that ...
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1answer
54 views

Finding release angle and final velocity of projectile when the target has a different coordinations [closed]

I am trying to write some codes for auto-snowball mechanism which seems like a regular projectile but instead of hitting the targets on the ground it is going to be able to hit the target in the air ...
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1answer
41 views

Kinematics with non constant acceleration II [closed]

I'm getting crazy with this problem and I think that it's pretty simple. An helicopter's helix is spinning at initial speed $w_0=200\ rpm$, all of a sudden the motor stops and it decreases its ...
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2answers
108 views

A bird problem and trains [closed]

So that the problem: There are 2 trains at speed of 30km/h in the same trail and opposite directions and moving for a collision at 60km of distance of each other. One bird in front of one of the ...
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1answer
41 views

Determining the horizontal position of an object [closed]

In my calc-physics class we were given the following question: A movie stuntwoman drops from a helicopter that is $30.0 m$ above the ground and moving with a constant velocity whose components are ...
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1answer
249 views

Relative motion and how to calculate magnitude and velocity of objects relative to different given objects [closed]

A canoe has a velocity of 0.550m/s southeast relative to the earth. The canoe is on a river that is flowing at 0.540m/s east relative to the earth. Alright so I attempted many different things an ...
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1answer
91 views

Finding an equation to solve for the velocity of a swimmer crossing a river [closed]

Where $\theta=45^\circ$, $d_1=200\:\mathrm{m}$, and $d_2=150\:\mathrm{m}$. I do not know how to combine the following equations: $$\begin{align} t&=\frac{d_1}{v_s\cos(45^\circ)}\\ ...
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2answers
32 views

Simple velocity and kinematics!

in this question, how to i solve for the velocity of object at point W? What my thinking was is that you know x to w is 25, therefore 25m/25s = 1s so 1s/2 = 0.5s, so: v = d/t = 25/0.5 this is ...
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1answer
160 views

Help understanding a potential energy problem [closed]

Apologies if the following problem does not seem to involve potential energy, it is a homework problem that is labeled under the potential energy chapter. Question While a roofer is working on a ...
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2answers
46 views

A Kinematics Problem [closed]

Problem: From the top of a building of height h = 100 m I throw a stone up with velocity 10 m/s. What is the maximum height it reaches, and when does this occur? First I solved for $h_{max}$, ...
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1answer
184 views

Calculating angle of projectile motion [closed]

I realize that similar questions have been asked but I'd like to put my problem here and what I have to make sure everything is right. So my problem is: I've got a rock $2.5$ meters above the ground ...
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2answers
142 views

Difference between the two equations for acceleration

I came upon this while studying S.H.M. Well,is there a difference between writing $$a=\frac{dv}{dt}\;$$ and $$a=v\frac{dv}{dx}\;$$ do they differ on the basis of one being a vector and the other ...
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1answer
105 views

Parametric equations in ballistics

while studying some material on ballistic trajectories (the basic gravity-only parabola), I've tried to come up with closed-form expressions for another case, where in addition to gravity we add a ...
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1answer
82 views

Homework: A parachutist jumps from a plane [closed]

I need help with the following problem. I think I almost have it . . . A parachutist bails out and freely falls a distance of $y_1$. Then the parachute opens and thereafter, the parachutist ...
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2answers
193 views

Finding the optimal angle of a projectile motion [closed]

I am trying to solve a task in which I need to calculate the optimal angle($\alpha$) with which the projectile will land the furthest from a height ($h$), so what I basically have is the equations for ...
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1answer
133 views

Missing centrifugal acceleration

I am trying to get correct equations for acceleration of a point in reference frame A, given position, velocity and acceleration in rotating reference frame B. Let $\mathbf{x}_A(t)$, ...
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1answer
131 views

Write a parabolic equation in kinematics

How might I go about writing a parabolic equation in standard form $ax^2 + bx + c$ given all of the following measurements: $X_0, X_f, Y_o, Y_f$: the initial and final x and y positions. ...
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1answer
192 views

Vector Maths to Simulate Car Physics [closed]

I'm working on a 3D program that involves controlling a Cube on-screen (which represents a car). I use C++, OpenGL and GLM (for vector and matrices etc, if you're familiar with programming; Once the ...
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1answer
121 views

x-coordinate of the ball when it's velocity is perpendicular to projection velocity

We have a ball projected at 20 m/s at an angle $\pi/6$ from the x-axis. Now we have to calculate x-coordinate of the ball when it's velocity is perpendicular to projection velocity. I am thinking ...
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1answer
193 views

Muon 3 Body Decay

I'm trying to calculate the maximum energy of the electron in the decay muon >electron + electronantineutrino +muonneutrino in the reference frame of the muon having no kinetic energy. $m_m$=mass of ...
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1answer
270 views

Height of projectile above the inclined plane and above the horizontal.

I am trying to work out the maximum height of a projectile above the incline plane and above the horizontal plane but I am not sure how to do this. I have worked out all the equations of motion, $ax, ...
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2answers
594 views

Why does the amount of energy transferred depend on distance rather than time?

The change in energy of an object can be determined by the work equation, where work is the change in energy: $$ W = F \cdot d $$ I conceptualize the transfer of energy as simply a series of small ...
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1answer
995 views

Average Resistive force exerted by a wooden block on a bullet [closed]

A bullet of mass 0.04 kg moving with a speed of 90 m/s enters a wooden block and is stopped after a distance of 60cm. What is the average resistive force exerted by the block on the bullet? Ok, so ...
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1answer
56 views

Uniform Acceleration [closed]

A steel ball is allowed to roll from rest down a 20.0 m long slop and over a 25 m long level surface. It takes 4.0 seconds to roll down the slope. Calculate the speed at the bottom of the slope. ...