The rate of change of velocity of a body per unit of time.

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2answers
103 views

I don't understand the formula of constant deceleration required to prevent a vehicle collision

As I was looking for the formula that an Intelligent Speed Assist technology use to calculate the required deceleration that a vehicle must apply avoid collision, I found this one: $$a = \frac{V^2_0 ...
0
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3answers
84 views

Gravitational acceleration of asteroids [closed]

If an asteroid is moving through space at a speed that exceeds escape velocity of the earth and that asteroid is on a collision course with the earth will the asteroid Accelerate as it falls into the ...
0
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1answer
30 views

From a displacement-time table/graph, can one tell whether acceleration or jerk is constant?

Does constant acceleration equal a parabolic graph similar to $y=x^2$, while jerk follows the path of $y=x^3$? I was just thinking about this possibility. We are always told in physics class that ...
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1answer
68 views

Why does centripetal acceleration equals $v^2/r$?

I have found something on wikipedia, but I don't understand why does the $v(t) \frac{\mathrm du_t}{\mathrm dt}$ equals with $\frac{v^2}{r} u_n$.
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1answer
135 views

Find constant acceleration needed to reach point (possibly related to projectile motion on slopes) [closed]

Given a particle with a position $p_0$ and an initial velocity $\vec{v_0}$, what acceleration $\vec{a}$ do we need to reach point $p_1$ and how long until we have reached $p_1$? The magnitude of the ...
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0answers
12 views

Pulley Advanced Equilibrium Problem [duplicate]

How to show that M would have to be more than 8m
2
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0answers
22 views

Position, velocity, acceleration, jolt, and [duplicate]

I am familiar with the fact that $\displaystyle{\frac{dx}{dt}}=v$, $\displaystyle{\frac{dv}{dt} =a}$, and $\displaystyle{\frac{da}{dt}=J}$ where $J$ denotes the 'jolt', or jerk. Are further ...
1
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1answer
61 views

Acceleration due to gravity [closed]

Why is it difficult to drink water inside the artificial satellite in the space? I think one of the reasons is that there is no gravity in space and hence we cannot drink water. but I am not sure ...
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3answers
102 views

Components of gravity in an inclined plane

The reason the block accelerates down the inclined plane is that the resultant of $N$ and $mg$ acts down the incline. However, why is the force causing the block to accelerate down the incline often ...
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1answer
24 views

Question on weightlessness

An astronaut in an artificial satellite of the earth feels weightlessness. Do they feel weightlessness on the moon too? Why? An astronaut in all artificial satellite feels weightlessness due to the ...
0
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0answers
9 views

Is it possible to find the G forces of one of the axis rather than the total?

I am investigating the g-forces and acceleration experienced on roller coasters and have data for $x$, $y$ and $z$ acceleration every $0.2$ seconds of the ride as well as the total acceleration and ...
1
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1answer
41 views

Can an accelerometer be used to determine orientation of a rocket under power?

I saw a project on Hackaday featuring a model rocket with moveable fins to stabilize the rocket's trajectory: Hackaday. The goal was to arc the rocket to a horizontal trajectory and keep it there. In ...
0
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2answers
32 views

Acceleration due to gravity at Centre

Why is the acceleration due to gravity at the center of the earth $0$? My Attempt actually at the center distance from the surface is equal to the radius so the formula $$g'=(1-\frac{d}{R})\times g$...
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0answers
39 views

Relating Initial velocity and acceleration to distance traveled up a ramp

This is the situation: I am conducting research on the ability of fin-fish to scale short wetted ramps for use alongside sea-lamprey barriers to allow non-target species to pass these barriers. We ...
-1
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1answer
29 views

Net force equal to mass multiplied by acceleration of centre of mass [closed]

$F=ma$ if $a=0$ then definitely the net force applied will be also zero (0). then, in this case $m=F/a$. If both net force and acceleration(of centre of mass) is equal to zero (0). then, isn't mass ...
0
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0answers
39 views

How does Einstein's curved space time produce acceleration in a free falling object? [duplicate]

I never really thought much about all of this before so I'm definitely a newbie. Please excuse my ignorance. If I understand what I have read so far: if spacetime is curved time would click by at a ...
0
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1answer
34 views

Why is the acceleration of the center of mass is equal to 0 in this problem?

I don't understand why the center of mass' acceleration is equal to 0 when the center of mass should be moving as an external force is exerted on the cue ? Billiard Balls. Now we can go back and ...
0
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2answers
142 views

How to calculate acceleration from discrete samples of velocity?

I have a device that I made which is able to calculate distance moved and can determine time. I take samples of time every x distance. Giving me n velocity samples. I currently show the user 2 ...
0
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1answer
74 views

What is $\omega \times v$?

I found that equation in my textbook. It says that $\omega \times v$ ($v$ is velocity) is centripetal acceleration. But how is the equation derived?
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0answers
22 views

Do all objects free fall at the same rate regardless of their mass? [duplicate]

Is it true that all object will fall at the same speed in vacuum irrespective of their mass because the acceleration due to gravity of Earth is 9.8 m/s2. Then what happens to the gravitational force ...
0
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2answers
49 views

Force on a Massless String

Suppose we are just pulling a block with the help of a string which is massless. Now since the mass of the string is 0 the force exerted by us is transmitted without being diminished. So the equation ...
0
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2answers
32 views

How to calculate the acceleration, if the mass-center is not on the force-vector's line (2D)

In a 2D plane there is an object, whose center of mass is at the $P$ point. The mass of the object is $m$. We apply a force $\vec F$ at the point $A$. If the center of mass is on the line, defined ...
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1answer
87 views

How does acceleration feel compared to gravitational pull?

I was debating a variation of this Phys.SE question with a friend. The original question is: "If you had your eyes closed, could you distinguish between standing still on earth and being in a ...
1
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1answer
25 views

What is the minimal G-force curve in 2-dimensional space?

Given two parallel roads, which need to be connected, what shape of curve would produce the minimum overall horizontal G-force(s) on travelers? Is it a $sin$ or $cos$ wave? Is it a basic cubic ...
0
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1answer
76 views

Different forms of centripetal acceleration

For a circular motion centripetal acceleration can be expressed as $$a_{c}=\frac{v^2}{R} \hat{u_N}\tag{1}$$ Where $\hat{u_n}$ is the normal unit vector. Nevertheless in the expression for ...
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5answers
110 views

Elevator normal force

In the above case, the normal force exerted by the elevator on the box would be $= 10\mathrm{kg}\ g + 10\mathrm{kg}\ 5\ \mathrm{m/s^2}$, assuming $g = 10\ \mathrm{m/s^2}$, the elevator would exert a ...
1
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0answers
57 views

Determining the forces required to maintain a static center of mass position; one with velocity and one with acceleration [closed]

I'm having a bit of trouble wrapping my head around this conceptually. The magnitudes and directions of the forces on two of the particles are indicated. What are the magnitude and direction of the ...
-1
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3answers
58 views

How to show that distance travelled in the $n$'th time interval grows in arithmetic progression [closed]

$\mathbf Q.$ A car starting from rest and accelerating uniformly travels a distance $d$ in the first $n$ seconds and a distance $k$ in the next $n$ seconds. Prove that $ k=3d$ Attempt: $$d=(v_1)(n)$$...
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1answer
37 views

Infinite acceleration of bob in pendulum with no friction or air resistance

So i'm a bit confused about something. If we take a mathematical pendulum and we apply a force to it. We ignore all friction and air resistance and only consider gravity and the force applied to bob. ...
0
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0answers
33 views

How to derive velocity, distance from a changing acceleration?

I'm making a electronic device that is out of the scope of this site, but essentially it gives me acceleration readings every X microseconds. Given these samples of acceleration, how can I find out ...
0
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1answer
45 views

How to simulate an accelerometer in code

I want to write a simulation of an accelerometer (with a fixed X and Y axis in this case but with respect to a world coordinate frame) on a stick, rotating in a circle around a fixed point. From that ...
0
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1answer
63 views

Angular Acceleration of a Pendulum

I am trying to work out the mathematics behind the design of an old mechanical brake tester. The device sits in the passenger foot well of a vehicle and tests the brake efficiency. The device is ...
0
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1answer
20 views

Physics of Auto Crashes and Airbag Modules

I recently saw a post (that was pretty old) asking why we don't consider the jerk function more often in sciences that deal with impacts or sudden accelerations. The general belief was that impacts, ...
1
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2answers
66 views

Dynamics of swinging

My husband built a 20'-high tree swing, using 3/16"-welded-link chains to suspend it approximately 2' off of the ground. To our disappointment, pumping barely gets the swing going, with little height ...
4
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2answers
88 views

The two causes for the factor 2 in Coriolis effect

While reading this document on Coriolis effect http://empslocal.ex.ac.uk/people/staff/gv219/classics.d/Persson98.pdf, I saw the followig sentence Two kinematic effects each contribute half of the ...
2
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1answer
51 views

Contraction of a rotating system

Consider a system of two masses that rotates with constant angular velocity. When a force contracts the system the velocitie of the two masses increase. I understand this in terms of conservation of ...
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1answer
41 views

How do you know when to use kinematic equations as apposed to $v = d/t$ and $a = v/t$? [closed]

How do I know when to use v = d/t and a = v/t or d=vi+​1/2​​at^2 and vf = vi + at?​
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4answers
95 views

Question related to accleration due to gravity [closed]

What effect will be seen on the value of accleration due to gravity if radius of the earth is decreased keeping the mass constant?
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2answers
45 views

Acceleration due to conservation of angular momentum in absence of a force

I don't understand why the conservation of angular momentum can imply an acceleration, in absence of a force. Consider for istance planetary motion. The angular momentum $\vec{L}$ of the planets is ...
0
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5answers
201 views

Why do heavier objects fall faster on hills but not in straight drops?

All other things being equal, if a heavier object will roll at a higher speed down hill than a lighter one, because it's heavier with more mass, then how is it that dropped objects fall at the same ...
0
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2answers
57 views

Position, velocity and acceleration vs time graphs

I'd like to draw graphs of a vehicle and I have a position vs time table. I can set the points but how am I supposed to join them, straight or hyperbole ? If the object is accelerating which is yes ...
0
votes
2answers
62 views

Which formulas can be used instead of $\frac{1}{2}kx^2=\frac{1}{2}mv^2$, when we are solving a mathematical problem related to horizontal spring? [closed]

Let, contraction of a horizontal spring, $x$, is $4$ cm and mass of a bullet, $m$, is $10 g$. Spring constant, $k$, is $200 N/m$. When bullet leaves the gun, what will be the velocity of it? Can I ...
8
votes
1answer
147 views

Acceleration of particle “held in place” at $x = 1$ [closed]

The metric components in a two-dimensional spacetime are given in terms of the coordinates $(t, x)$ by$$ds^2 = -\cosh x\,dt^2 + dx^2.$$Consider a particle that is "held in position" at $x = 1$. What ...
0
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0answers
33 views

Centripetal acceleration in polar coordinates

$ \left( \ddot r - r\dot\varphi^2 \right) \hat{\mathbf r} + \left( r\ddot\varphi + 2\dot r \dot\varphi \right) \hat{\boldsymbol{\varphi}} \ $ I'm not convinced about the term $- r\dot\varphi^2 \hat{...
0
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0answers
127 views

Calculating travel time based on distance, velocities, acceleration, and jerk

Not much physics background so please bare with me. Say we have an object traveling on a straight line going from x to y. We know the starting velocity at x, the velocity when y is reached, the max ...
0
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2answers
83 views

Why does force cause acceleration?

Consider a ball placed on a smooth plane. If you take a plank made out of wood and whack it (apply a force on it), does it accelerate because First, the force compresses the part of the ball in ...
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2answers
60 views

Infinitesimal time intervals use

I've a question, that maybe will sound obvious, on the use of infinitesimal quantities. Consider the expression for the acceleration in non inertial frames. $\frac{d\vec{v}}{dt}=\frac{d\vec{v'}}{dt}...
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3answers
57 views

Physical interpretation of Coriolis terms in acceleration

Consider a reference frame which is rotating (for example on a carousel) and a steady inertial frame, with the same origin. $\vec{r}=\vec{r'}$ $\vec{v}=\vec{v'}+\vec{\Omega}\times\vec{r'}$ $\vec{a}=...
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1answer
89 views

“Spacetime tells matter how to move; matter tells spacetime how to curve” and acceleration in flat space-time? [closed]

John Wheeler stated "Spacetime tells matter how to move; matter tells spacetime how to curve." Does this contradict with the assumption that mass can be accelerated in flat space-time (see i.e. this ...
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3answers
54 views

Why the similarity in the Equations of Motion for Rotational and Rectilinear Motion?

These are the equations of motion given constant acceleration, for first rectilinear and then rotational motion. Rectilinear Motion: Rotational Motion: While the variables have changed, and the ...