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

learn more… | top users | synonyms

0
votes
0answers
23 views

Is gravitational acceleration less affected by relativistic mass increase? [duplicate]

Acceleration due to mechanical force will lessen due to relativistic mass increase as kinetic energy becomes significant near c. But if acceleration is gravitational, the gain in relativistic mass ...
0
votes
2answers
42 views

How should two particles accelerate to have their separation Lorentz-contract?

Suppose we have two particles with initial separation of $|x_2^\text{init}-x_1^\text{init}|=d$. At time $t=0$ they start accelerating with proper acceleration of $w$. Then position of the $i$th ...
1
vote
1answer
69 views

What is the difference between negative acceleration and decreasing acceleration?

According to Reisnick and Halliday, retardation is the acceleration in the negative direction of time axis ie. opposite to the motion. Decreasing accleretion is the decrease in the magnitude of time ...
0
votes
2answers
31 views

Peak at zero in one device and not the other

I was wondering if anyone could shed some light on this problem. I have placed two accelerometers on an animal one sampling at 50 Hz the other at 100 Hz. They were placed in the same position. I then ...
0
votes
2answers
68 views

$F=ma$ calculation taking relativity into account?

Newton's second law of motion states that $f = ma$. However, in this equation, theoretically there could be a value of $f$ and $m$ that results in an acceleration that is enough to push an object past ...
1
vote
3answers
44 views

Momentum acceleration in space?

I'm an engineering student and have a few ideas to bat at the scientific community. First premise is based upon common sense. I understand that if I am standing on a skateboard on a relatively smooth ...
2
votes
1answer
25 views

Does Light (EM Signal) undergo accelration during reflection? [duplicate]

Since Average acceleration is defined as, Average acceleration over a period of time is the change in Velocity divided by the Duration of the Period. Does Light (EM Wave) undergo acceleration during ...
1
vote
3answers
32 views

Is there a difference between “average acceleration” and centripetal acceleration?

Question adapted from Examkrackers MCAT prep book: A particle moves along a half circle (diameter=$10\text{ m}$) at a constant speed of $1\text{ m/s}$. What is the average acceleration of the ...
1
vote
0answers
23 views

Do we feel the full force of the earths gravity even though the earth is spinning [duplicate]

As far as I know, since the earth is spinning, centrifugal force should be throwing you off the earth. However, gravity counteracts that by being a stronger force. So if you stood an object with the ...
1
vote
2answers
44 views

What is the value of $g$ at centre? [duplicate]

What is the value of $g$ at the centre of the Earth? Is it zero or infinity? My attempt: I know it's zero but applying law made me on fused.
3
votes
1answer
73 views

If dark energy is accelerating the expansion of the universe, why can't I feel it?

Based on the Lambda-CDM cosmological model, our universe is not only expanding, but is accelerating in its expansion. However, the Equivalence Principle would suggest that inertia manifests itself in ...
0
votes
1answer
34 views

What will be the acceleration of an object $A$ when its released by another object $B$ moving with an upward acceleration $a$?

What will be the acceleration of an object $A$ when its released by another object $B$ moving with an upward acceleration $a$? Will the acceleration of the object $A$ be more than the acceleration due ...
2
votes
3answers
47 views

Can we measure rates in real time?

I know what it means to say that my position is "X" at a particular moment in time. I can easily take a picture of my motion and observe my exact location at the instant the picture was taken. That is ...
1
vote
3answers
145 views

Calculate vertical distance using acceleration

I have the following scenario: an iPhone is connected to a vertical rail (it's motion is restricted to the Y axis). Through mechanical means the phone is forced upwards and then allowed to return to ...
6
votes
5answers
234 views

Acceleration in $F=ma$

I tried to ask this question in Electrical Engineering Stackexchange but was told I was better asking here. Newton's Second Law of Motion states that the vector sum of the forces $\mathbf{F}$ on an ...
0
votes
1answer
30 views

Force felt by capacitor mounted on printed circuit board

I have a printed circuit board with a surface mount electrolytic capacitor soldered to it. It has two spindly legs that hold up this can, so it can move back and forth on the legs' axis just slightly. ...
1
vote
0answers
15 views

Is acceleration quadratic or linear outside of a gravity field? [duplicate]

So as I understand it: If you hit a wall at twice the speed you hit four times as hard? I often ask people this and everyone says "at twice the speed you hit twice as hard". $K=\frac{1}{2}mv^2$ is ...
2
votes
2answers
78 views

How do we know gravity isn't acceleration? [closed]

If an accelerometer sitting at rest on the earths surface measures 1 G of acceleration upward. How do we know "space" (the reference) isn't rushing down into the earth. I mean experimentally that's ...
0
votes
1answer
37 views

Bomb trajectory from an airplane

If a plane is flying at a constant speed at some altitude like 5-6 km and it releases a bomb: does the bomb move forward at the same horizontal speed as the airplane? or does its horizontal speed ...
1
vote
0answers
25 views

what does exactly accelerometer measure on a vertical rotating disk?

I am trying to understand an aspect of rotational dynamics. I am having some trouble arriving at a solution. Consider a disk of uniform mass distribution, and radius R centered at the origin of an xy ...
1
vote
2answers
38 views

Help explain how direction change relates to acceleration [duplicate]

I was doing some simple harmonic motion problems and I came across this picture describing the position, velocity and acceleration of a linear oscillator. At the moment in time when v is 0 the ...
9
votes
5answers
325 views

What is the best path for a given initial and final state?

I am trying to calculate an efficient acceleration curve given starting and final positions and velocities. I'm assuming no friction, and that the acceleration can be applied in any direction at any ...
0
votes
0answers
28 views

How to calculate the equation of projectile motion for curved ramps? [duplicate]

Consider the following cases (these are sections): I can find the equation of motion for Case a however I don't know how to deal with Case d. Normally I would need the angle α otherwise I can't ...
2
votes
1answer
101 views

How to find equation of motion for this trajectory? - object leaves curved ramp at a given velocity [closed]

Here is the sketch: The sketch is supposed to be side-view of the path of the object. The following values are known: $r$ - radius of the circle that describes the path AB of the object $a$ - ...
1
vote
1answer
78 views

Accelerometer problem - difficulty understanding my readout

I am having great difficult understand my readout from an accelerometer that I placed on a rotation wheel. The wheel spins at various speeds and i measured the radius from the center. I think I ...
0
votes
2answers
41 views

why precise accelerometer do not exist

When i read about how the concept works, it looks pretty solid. But in reality accelerometers are just so imprecise that they need to be configured with alternative ways to correct their positions. I ...
6
votes
2answers
87 views

At Interfaces Does Light Have to Accelerate?

First, I'm not sure if photons have to "get up to" the speed of light, or if they are thrown into existence at that speed. I know that they should just be generated moving at their speed, and I know ...
0
votes
1answer
37 views

Accelerometer validation trace

I am attempting to validate an accelerometer. I have a triaxial accelerometer and placed it on a wheel which goes at various frequencies from 1 to 3 Hz. Am I right in thinking that I would expect the ...
0
votes
1answer
33 views

How to use an accelerometer to correctly quantify the magnitude of vibrations

Consider the following setup, an accelerometer is placed inside a helicopter, measuring "g" values along 3 axes (x,y,z) every 10 ms (100 times a second), during a helicopter flight. If one, wants to ...
0
votes
1answer
52 views

Have I calculated Angular Acceleration correctly?

I am teaching myself basic mechanics from a standing start. I am trying to understand Angular Acceleration and have set myself a problem to solve. My answer 'feels' wrong, so I'd like some help to ...
0
votes
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 ...
0
votes
0answers
34 views

Geometric Interpretation of these equations of motion?

I was reading my Engineering Mechanics book, and it derived some strange looking integrals I'll have to apply. I could memorize them, but I'd rather understand them - then I won't have to memorize. ...
3
votes
2answers
97 views

What does an applied force on an already accelerating object do?

I'm a big beginner having only taken Grade 11 high-school physics. Imagine this situation: an object is accelerating north, and while it's accelerating, it's 'hit' by a northward force. To me it ...
23
votes
6answers
3k views

Why do heavier objects fall faster in air?

We all know that in an idealised world all objects accelerate at the same rate when dropped regardless of their mass. We also know that in reality (or more accurately, in air) a lead feather falls ...
1
vote
1answer
43 views

Travel time for accelerating object [closed]

I have an object which starts at velocity = 0. Accelerates to a known max speed and continues thereon at constant velocity (max speed). My problem: How long does it take to reach a known ...
7
votes
3answers
585 views

Dark Energy / Accelerating universe: naive question

Folks, I have a naive question regarding the subject of dark energy and an accelerating universe: From what I understand/read, it seems that the further we look out into deep space, the faster the ...
0
votes
2answers
37 views

Constant Acceleration Question [closed]

A Cessna 150 aircraft has a lift-off speed of approximately 125 $kmh^{-1}$. What minimum constant acceleration does this require if the aircraft is to be airborne after a take-off run of 129 m? So I ...
2
votes
1answer
26 views

am i finding the force correctly?

I am trying to see if I am doing a problem correctly. Problem Suppose you carry a 50kg sack of potatoes up two flights of stairs, a total height of 10m. How much work did you do? If it took you ...
2
votes
1answer
48 views

How to get time from equation of linear uniformly accelerated motion?

I have had a problem solving this equation for time (from Linear Uniformly Accelerated Motion (LUAM)): $$ s= v_0t + \tfrac{1}{2}at^2 $$ I'll appreciate if someone could provide me some step-by-step ...
0
votes
1answer
64 views

Why is speed/position relative but acceleration not? [duplicate]

I think i understand it now, if found this: link I know that position and speed are relative. There is no such thing as universal coordinates. Then why is acceleration absolute? Is the 3th and 4th ...
3
votes
4answers
180 views

Solving for motion of rotating rod using only Newton's laws?

I have a question that's been bothering me for years. Given a rod of uniform mass distribution with total mass $M$ and length $L$ that lies on a horizontal table (with one end fixed to the table ...
2
votes
3answers
65 views

How to calculate the velocity of this body? [closed]

Graph of a train (the body) is provided which starts from rest. What is the velocity after the train has 10 metres displacement? Thats the only things provided for the question, please help me ...
0
votes
2answers
27 views

Space travel using pair production

If the method for creating electrons and positrons from photons, as described in this article, were proven correct, would it be possible to use it for accelerating space ships – using only an energy ...
0
votes
2answers
84 views

Can acceleration be achieved without reaction mass?

In a previous question, I asked whether a flashlight can accelerate me. The answer is yes. This has led me to wonder, this is inferior to all other known propulsion methods in all aspects except one: ...
42
votes
4answers
7k views

If I'm floating in space and I turn on a flashlight, will I accelerate?

Photons have no mass but they can push things, as evidenced by laser propulsion. Can photons push the source which is emitting them? If yes, will a more intense flashlight accelerate me more? Does ...
2
votes
1answer
101 views

When photons are emitted, do they accelerate to reach the speed of light? [duplicate]

Photons are considered mass-less particle with a specific velocity but according to the electromagnetic theory, a photon is considered to have both energy and momentum. So what happen when they are ...
0
votes
1answer
89 views

Truck moving uphill, object suspended from ceiling, determine acceleration [closed]

A truck is moving with constant acceleration $a$ up a hill that makes and angle $\phi$ with the horizontal. An object of mass $m$ is suspended from the ceiling of the truck by a light cord. If the ...
8
votes
1answer
120 views

Why does acceleration seem not to be the gradient of gravitational potential?

Consider a spherically symmetric distribution of density $\rho(r)$. We can define the mass enclosed within each radius $r$ using $\frac{dM(r)}{dr} = 4\pi r^2 \rho(r)$, with the condition that $M(r=0) ...
1
vote
1answer
79 views

Acceleration in stationary spacetime

How would I show the acceleration vector $ a^\mu = u^\nu \bigtriangledown_\nu u^\mu = \bigtriangledown^\mu lnV $ for an observer instantaneously 'at rest,' where $u^\mu = dx^\mu/d\tau$ and $V^2 = ...
0
votes
5answers
165 views

Acceleration is zero, for non-zero net force

I understand a problem like this has already been asked, but I have not found an answer that makes it clear. A force is applied to a box on a table(lets ignore friction), and the box moves with some ...