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

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63 views

Relative acceleration of two planets orbiting a star

Let us suppose we know the radii and periods of two planets' circular orbits around a star -say Earth, Venus and the Sun-, which allows us to calculate the planets' centripetal acceleration, ...
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2answers
29 views

Finding equation for exponential deceleration

Let's say my ship's velocity during deceleration phase is given by: $$ v(t) = v_0 \exp(-k t) $$ where $v_0$ is the speed at the time of starting deceleration and $k$ is arbitrary constant. My ...
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3answers
44 views

How to find stopping distance of a car? [on hold]

I am trying to calculate minimum stopping distance of a car once the brakes are applied. I know the velocity at braking instant, i also know the distance from the obstacle. I found out that $$ d = ...
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1answer
37 views

Moment of Inertia: uniform rigid rod on smooth plane [closed]

Consider a rod of length $b$ and mass $m$ on a smooth horizontal plane. A force is applied to one end of the rod. What is the acceleration $a$ and angular acceleration $\alpha$ of the other end of ...
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2answers
34 views

Uniformly Accelerated Motion question

A ballast bag is dropped from a balloon that is 300 m above the ground and rising at 13 m/s. For the bag, find the maximum height reached. Now the book gives me this answer - $V_i$ = initial ...
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1answer
49 views

What is a nongeodesic orbit?

I have read that in the Schwarzschild spacetime for a nongeodesic circular orbit the radial acceleration becomes positive for $r<3r_S$. Intuitively, the acceleration should be negative, pulling the ...
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1answer
57 views

Can two bodies move with equal acceleration if forces acting on both are unequal?

In my textbook there is a case given that is to find acceleration and tension produced in a string passed over a frictionless pulley and attached with bodies of different masses at its ends. Now below ...
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2answers
199 views

Why are heavy things harder to lift?

According to multiple websites, any object in free-fall (no air resistance) on earth will accelerate towards the Earth at 9.8 m/s. If all objects fall towards the Earth at the same rate, regardless of ...
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3answers
277 views

Understanding bending light beam perpendicular to motion

I'm just reading a book about gravity. An example it gives is a spaceship accelerating. A beam of light travelling at right angles to the direction of movement of the spaceship enters it via a small ...
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1answer
64 views

How can we prove simply that acceleration for every freely falling body is equal to $g$? [duplicate]

If I allow two bodies of different masses to fall freely from same height towards the earth, how can I prove that the acceleration produced in both was constant and equal to gravity.
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1answer
45 views

What physics concepts support the observation of the book and paper falling together?

you place a sheet of paper on a book, it falls with it rather than being separated & slowed by air resistance. What physics concepts support the observation of the book and paper falling together? ...
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1answer
28 views

Creating vacuum in a glass by acceleration

Suppose we have a cylindrical glass at atmospheric pressure. The glass is put in a horizontal position such that the bottom of it (the closed end) is at the right side and the open side is on the ...
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1answer
32 views

Need help with acceleration question? [closed]

I don't understand how to solve this question involving two constant accelerations.
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2answers
129 views

Animating an Acceleration Vector - Acceleration of object on a crested path in gravitational field

So I was reading in Chapter 3 of my textbook, Sears & Zemanksky's University Physics with Modern Physics by Young and Freedman, 13th Edition, and the discussion took us to a definition of the ...
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1answer
21 views

Do all thing move against gravity with -9.8 meter per second squared acceleration?

If I throw a ball to height h above the earth's surface and then shoot a bullet that reaches the same height but would there be same quantity of acceleration produced in both?
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3answers
433 views

Does a heavy body move with the slightest force on a frictionless surface?

If I apply horizontal force on a body resting on the ground, my force will be opposed by the frictional force and the body will accelerate at the point where my force exceeds the force of friction = ...
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0answers
38 views

Accelerating rockets by periodic explosions? [closed]

Since in the outer space friction is almost 0, couldn't we accelerate a rocket to reach much faster speeds than that of the current limit by periodically starting and stopping the engines? I think ...
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3answers
47 views

Position, Velocity And acceleration relations

Today we showed our physics teacher our code for a basic physics engine. He told us that this code snippet is incorrect: ...
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0answers
12 views

Zero velocity and non-zero average acceleration

Can you have a zero velocity and nonzero average acceleration? I am confused with the word "average" here. If the question would be, "Can you have a zero velocity and nonzero acceleration?" my answer ...
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1answer
55 views

The ever increasing pull of a black hole

If something is caught in the pull of a black hole and keeps accelerating it can't keep accelerating with no limits or else it would accelerate beyond c. So is there a limit on how fast acceleration ...
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0answers
14 views

Is there a way to detect acceleration of an object using a magnetic field readings (magnetometer)

I intend to design an application for Android which uses the accelerometer to detect the acceleration. However I'd also like to use the magnetometer to reduce the noise from accelerometer readings. My ...
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2answers
322 views

Accelerating elevator?

If your in an elevator accelerating downwards faster than gravity, would you be pushed up to the ceiling? Since gravity cannot match the acceleration of the elevator, you're wouldn't be able to move ...
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1answer
42 views

Can we measure the acceleration with Newton

I have read before that 1 N = 1 m/s^2 And the m/s^2 is a unity for measuring the acceleration so i thought that we can represent acceleration in newton , can we ...
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1answer
36 views

Wheel slowing down with constant acceleration

A wheel of radius $R$ spins about its center with a centripetal acceleration of $v^2/R$. I get that the acceleration at all points on the rim of the wheel point towards the center of the wheel. But, ...
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3answers
10k views

Small car colliding with large truck

A small car collides with a large truck. Why do both vehicles experience the same magnitude of force? Wouldn't the large vehicle experience less force than the small one?
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2answers
373 views

Exact definition of momentarily comoving reference frame (MCRF)

Consider a particle $P$ in the framework of special relativity with position $r(t)=(ct,x(t),y(t),z(t))$ respect to an inertial reference frame $\Sigma=(ct,x,y,z;O)$. I need to know if the following ...
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5answers
230 views

Is the polar coordinate system non-inertial or inertial?

Consider a car driving around in a circle lying in the plane and suppose we were interested in determining its acceleration as measured by an observer stationary on the "ground" or whatever. ...
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2answers
103 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 three axes $(x,y,z)$ every $10~\text{ms}$ (100 times a second), during a helicopter flight. ...
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1answer
79 views

Energy for acceleration towards speed of light is relative?

This seems a very simple question - and I guess it will turn out to be so. It's a given that accelerating particles with mass towards the speed of light takes more and more energy (ultimately an an ...
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2answers
38 views

Can the law of the acceleration be applicable to a man falling from plane?

Is acceleration law $a = \Delta v/\Delta t$ applicable on somebody who is falling from an air plane? Does the acceleration increase when some body is at some altitude and does his speed increases by ...
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2answers
163 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 ...
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2answers
62 views

Acceleration of ball rolling down incline

Suppose you have some object (which can roll like a ball,cylinder,wheel,etc) rolling down an incline without slipping (moment of intertia $I=kmr^2$. I want to find the accleration of the ball as it ...
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0answers
42 views

Centripetal acceleration for a polyline

This question is also posted on the Mathematics forum. I am not physicist, therefore sorry if my question is a bit primitive. Given a polyline (x and y coordinates) in Cartesian coordinate system, ...
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1answer
26 views

Acceleration in a system equal for every body — why?

A 1 kg cart can slide frictionlessly on the table. The black weights each weigh 1 kg. The pulleys are frictionless. The task is to determine the acceleration of the cart. For the left-most ...
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1answer
53 views

Why is gravity not counted as acceleration in this problem?

I am doing physics homework and I noticed that the solution to this question specifies that the total vertical Force is 0. Since the two buckets (shown below) are hanging vertically, wouldn't I just ...
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2answers
35 views

Changing directions with a constant speed?

I'm currently working on a problem in which an object's speed remains the same, but it experiences a change in direction after some time. I'm fairly sure it experiences an acceleration in order to ...
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2answers
2k views

Classical car collision

I have a very confusing discussion with a friend of mine. 2 cars ($car_a$ and $car_b$) of the same mass $m$ are on a collision course. Both cars travel at $50_\frac{km}{h}$ towards each other. They ...
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1answer
27 views

What is the effect of Torque Steering on a motorcycle with a long wheel base

From experience, it appears motorcycles with a large wheelbase coupled with a long handlebar (say a modified Harley Ape Hangar) shows a noticeable tendency to veer to a side during acceleration vs a ...
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0answers
47 views

Instantaneous acceleration in non uniform circular motion

How is instantaneous acceleration different from tangential acceleration in a non uniform circular motion? We know that instantaneous acceleration is tangent to a point at any given time and so is ...
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2answers
43 views

Rate of deceleration for an average speed [closed]

I'm trying to figure out how to answer this problem: A car is driving at 11 m/s, when it begins to brake. Over the next 25 meters, it averages 6 m/s. At what rate does the car decelerate? Assume a ...
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3answers
86 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 ...
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1answer
67 views

Post-Newtonian acceleration formula

First of all, I have to say that I know very little about tensors and partial differential equations, as I've never done them at school. I'm developing an application which simulates the motion of ...
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0answers
35 views

Do charges attractions cause time dilation? [duplicate]

I was pondering whether charges will cause time dilatation? Let me explain more, well we know that gravity causes time-dilatation because of gravitational acceleration which is equal to: $$a = ...
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0answers
66 views

Why and how is acceleration absolute?

Is there a testable model which explains why rotation of an object in space and straight-line acceleration appear to be absolute while uniform translation is relative? I know of Mach's explanation, ...
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1answer
42 views

Accelerometer misalignment issue

I have tri-axial data from an accelerometer, however, I know in retrospect that it was not aligned properly when placed on a mechanical arm. I know because when looking at the values at stationary ...
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2answers
58 views

Solving distance with acceleration and velocity given and getting two different answers using two different equations [closed]

Frictional forces from brake pads are responsible for stopping an automobile. A car is moving at $35.0 \:\mathrm{m/s}$. If the car's brakes are capable of generating a deceleration rate of $6.00 ...
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1answer
359 views

Does a ball resting on the ground have acceleration?

Does a ball resting on the Earth's ground have acceleration caused by gravity?
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2answers
131 views

Speed cannot be greater than speed of light. How about acceleration? Does it have limit?

We know that $c$ is the largest speed in the universe. How about the acceleration, does it has limit?
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1answer
91 views

Electrons and Magnetism

Electron at rest generates Electric field. Electron moving without acceleration produces electric and magnetic field. Electron moving with acceleration produces electromagnetic waves. Please explain ...
8
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2answers
1k views

Slinky base does not immediately fall due to gravity

Why does the base of this slinky not fall immediately to gravity? My guess is tension in the springs is a force > mass*gravity but even then it is dumbfounding.