Questions tagged [acceleration]

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

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Acceleration when motion is constrained by rope

The following is a question form HC Verma (Newton's Laws of Motion). I am not able to understand that if we consider the body of mass $M$ to move downwards with acceleration $a$, then why would the ...
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What is a negative force actually?

If we find the force for a decelerating object (let's say a car on a road), we'll see that the force is negative as in it’s in the opposite direction of the motion of the object. I wanna know what ...
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The direction of the velocity of a body can change when its acceleration is constant. How is it possible since acceleration is a vector quantity?

As we already know that acceleration is a vector quantity which means that it has both direction as well as magnitude. It can also change given any one of the two or both (magnitude and direction) ...
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Acceleration and Reference Frames

If I'm in a car and hit the gas, an outside observer on the ground sees my car accelerate to some speed, and given the mass of my car and the horsepower of my engine, this obeys Newton's second law. ...
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Maximum value of angular acceleration

In a video of Prof. Walter Lewin, in which he is talking about the maximum value of angular acceleration, he says that it does not imply that the angular acceleration is zero if the angular velocity ...
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Use of net acceleration in circular motion

We know there are two types of accelaration in circular motion, one is centripetal acceleration and the other one is tangential acceleration. The resultant of these two is the net acceleration $a$. ...
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Velocity as a function of time [closed]

Deriving velocity as a function of time. A particle of mass $m$ has velocity $\dot{x}$ at $x = 0$ and $t =0$. It travels along $x$-axis subject to drag force given by $F(\dot{x})=-c\dot{x}^{3/2}$ ($c$ ...
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How to explain the accelerated expansion universe

enter image description here Some textbooks describe accelerated expansion with an H value, as shown in the two figure above. It is said that the H value is accelerated because it is smaller in the ...
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Calculating the negative force with $F_{\mu}=N_{\mu}$ [closed]

If a 300kg vehicle is decelerating from $10\,\text m/\text s$ to $5\,\text m/\text s$ during 1000 meters, how can I calculate the negative force (the decelerating force)? According to this equation $...
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How is position calculated when the acceleration is not constant?

To get the position of an object we can use the equation: $$x=x_0+v_0t+\frac{1}{2}at^2$$ But now I don't have a constant acceleration, both $x_0$ and $v_0$ start at $0$ and $v$ ends at $16 \text{ m/s}$...
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Does an object rolling down a slope have more momentum than a object in free fall?

Physics newbie here. I am trying to figure out in which of the following scenarios would the object end up further from the starting point: Will a car that veers off a road that has a vertical cliff ...
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Distance and velocity increased by $g$ units every second

Distance fallen in every second gets increased by $g$ units. Velocity is increased by $g$ units every second. Is it true that distance and velocity increases by $g$ after every second? If it starts ...
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How to obtain position data from acceleration without forward euler?

I am doing a investigation into the Wilberforce Pendulum and in order to find the position and rotation at any time I have attached my phone onto the pendulum in order to use Phyphox, a app that finds ...
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Is centripetal acceleration almost perpendicular to velocity or it is exactly perpendicular to velocity?

In all the derivations of centripetal acceleration that I have seen so far, the direction of acceleration is said to be perpendicular to velocity but I think it's not exactly perpendicular to velocity ...
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When a car accelerates relative to earth, why can't we say earth accelerates relative to car?

When a car moves away from a standstill, why do we say that the car has accelerated? Isn't it equally correct to say that the earth has accelerated in the reference frame of the car? What breaks the ...
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Friction and Newton's Laws of motion

I came across the following problem. Ok, I thought that assuming there is no friction between blocks B and C, when the blocks B and A will move, the block C will go to the right due to the force by ...
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Free-falling electron [duplicate]

An electron freely falls in the Earth's gravity, while being enclosed in a cylinder that contains energy detectors. The electron accelerates and therefore radiates energy, which is detected. However, ...
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Would the fast rotating legs of a human age slower? For how much?

Let's imagine that there is some human that rotates rapidly around his head. That means that the legs have a very large velocity, but the head has the velocity nearly equal to zero. Let's just ignore ...
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Calculating lateral/longitudinal acceleration/jerk

I know how to calculate the lateral and longitudinal velocities given the velocity (v) and heading angle (theta): v_lat = v*sin(theta) v_long = v*cos(theta) But ...
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Difference between Instantaneous Velocity and Acceleration?

I'm studying the Speed and Velocity chapter. But there isn't anywhere mentioned in my book about clarity for the exact difference between Instantaneous speed and Acceleration. I'm curious to know ...
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Derivation of acceleration of center of mass of pulley [closed]

Let the two extreme ends of massless frictionless pulley accelerate with acceleration $a_1$ and $a_2$. Prove that the center of the pulley has an acceleration $\frac{a_1+a_2}{2}$. My method: The ...
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If an object accelerates more than $g$ (9.81m/s/s), wouldn't it weigh more than when it is at rest?

Weight is a force. Correctly measured in Newtons, not kilograms. Weight is a product of mass times acceleration. That's Newton's Second Law. Rest-weight is mass times $g$ the gravitational ...
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Why is the rate of change of velocity with distance not constant?

My physics textbook says, "Galileo concluded that the rate of change of velocity with time is a constant of motion for all objects in free fall. On the other hand, the change in velocity with ...
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Does relativity mean that the crew of a relativistic rocket would experience less acceleration than in our frame of reference?

I have been told regarding a 1 g rocket that "the amount you accelerate would be less due to relativity". Does that mean that from the crew's time dilated perspective, they would experience ...
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What is the acceleration magnitude of a simple pendulum?

I'm trying to find the acceleration vector of a simple pendulum. The vector is labeled a in this image from Wikipedia: Trying to solve it, I've split the acceleration into perpendicular components: ...
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Does a long vertical pole fall at a different speed than a short vertical pole?

The formula for a falling object has $r^2$ in the denominator. This would mean that an object that is higher up falls more slowly than the standard $9.807\ \mathrm{m/s^2}$ that we are taught in high ...
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Why does the principle of relativity hold between two inertial observers when one of them had to accelerate?

I've been studying Special Relativity, and am in need of some clarification on the Principle of Special Relativity. I understand that if there are two inertial observers with a constant relative ...
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How does acceleration relate to the rate of change of speed?

I am given the following question: The trajectory of a charged particle moving in a magnetic field is given by $\textbf{r}=b\cos(\beta t)\textbf{i}+b\sin(\beta t)\textbf{j}+ct\textbf{k}$ where $b,\...
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What is behind a Rindler horizon? Or is there nothing?

Most of my friends say that a Rindler horizon is an artefact of acceleration. Space continues behind it. A few of my friends say that the Rindler horizon is an event horizon and a particle horizon. ...
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How can we calculate $g$ force in this maneuver?

How can we calculate $g$ force in this maneuver? We are not dealing with conventional maneuvers like level turn or loop so what equation used to calculate g force in this maneuver? What about other ...
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Can a relativistic rocket ever dilate time enough to be practical? [duplicate]

It seems the best shot for humans to visit other stars is a relativistic rocket, such as the hypothetical 1g rocket, which would dilate time in order for the mission to be completed in the crew's ...
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If General Relativity were only a theory of accelerated frames, would it contain the Equivalence Principle?

In Relativity: the special and general theory, Einstein motivates General Relativity by the need to extend relativity not only to inertial frames, but also to accelerated frames. The laws of physics ...
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Acceleration of a rotated point using rotation matrices [closed]

I am trying to calculate the acceleration of a point using rotation matrices and struggle to get my head around them. Imagine an inverted pendulum which can rotate about its x-axis but not any other ...
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Why is force equal to mass into acceleration?

If I'm sitting on a chair I'm exerting a force on it but my body isn't even moving so it doesn't even have a velocity. Then how can it even have a change of velocity i.e, acceleration?
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Can extreme acceleration (or space expansion) disintegrate a proton?

I have read this question: It worked in a similar way to dark energy but was so strong it would easily tear atoms apart Attractive higgs force and inflation And this one: Within mainstream physics ...
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Regard Two Objects As One

I was trying to solve the following exercise (apologies in advance for potential mistakes in terminology); illustration will be attached below: An object with mass $M$ is placed upon a frictionless, ...
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Accelerated through a potential difference

Say a electron is accelerated through a potential difference of 10v established between two points A and B 1metre distance apart. Then would i only be able to say that a electron is accelerated ...
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Centripetal force equation doubt

In a centrifuge, $a_c$ should be constant. If $m$ increases, the $r$ will increase in order to maintain a constant $a_c$. Constant centrieptal acceleration is given by $a_c={ v^2 \over r}$ and $a_c = ...
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Quantum gravity in an accelerated frame of reference

It is said that we can't study quantum gravity because gravity is a weak force. But gravity and acceleration are the same. Why can't we study quantum gravity in a strongly accelerated frame of ...
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Where does pseudo force act at?

It is known that, to apply Newton's laws in a non-inertial frame, we use the concept of pseudo force. We also know that force is a bound vector. Hence, is there a general way to determine where the ...
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Should the stars of a relativistic binary system have tangential acceleration?

Should the stars of a relativistic binary system have tangential acceleration?
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Acceleration as $\frac{D\vec u}{Dt}$ in the case of unsteady flow

In the book of Acheson, it is stated that the material derivative $\frac{D\vec u}{Dt}$ can be considered as an acceleration of a "fluid element" - which is something the author never defined,...
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Cylinder rolling on inclined plane

Let’s consider a rolling cylinder on an inclined plane with some friction. We knew that $\alpha R=a$, where $\alpha$ is the angular acceleration of each constituent particle and $R$ is the radius of ...
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The optimal time to start decelerating a craft landing directly on a planet

I was playing around with Kerbal Space program and I came across this issue that I hope somebody could help me with. Suppose there is a craft accelerating radially toward a planet due to gravity, with ...
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Angular momentum in rotating non-inertial reference frame

I know in inertial reference frame rigid body we can write $L=I\omega$ where $L$ is the angular momentum of the rigid body, $I$ is the moment of inertia and $\omega$ is the angular velocity of the ...
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Leaking freight car problem - Help understanding a solution

I'm dealing with the leaking freight car problem: A freight car is loaded with a water tank. The mass of the freight car and the filled water tank is from the start $m_0$. At time $t=0$ a horisontal ...
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How Does a Rocket Even Go Up? [closed]

The earth pulls all bodies towards it at $9.8\ \mathrm{m/s^2}$. I would like to imagine that the ground is accelerating up at $9.8\ \mathrm{m/s^2}$ (just as an analogy). So this means that a rocket ...
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What is the time derivative of the linear velocity vector $\vec{v}\,(t)$?

If $\vec{v}\,(t)$ denotes linear velocity, we can then write $\vec{v}\,(t)$ as $|v(t)|\hat{v}$. My question is what is $\displaystyle\frac{d\vec{v}\,(t)}{dt}?$ The answer I have seen to this question ...
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Contraction between metric tensor and non-tensor entity

In general relativity, I know that $$u^\mu=\dfrac{d x^\mu}{d \tau}$$ and $$a^\mu=\dfrac{d u^\mu}{d \tau}$$ where spacetime coordinates of a particle are a function of proper time and they are not ...

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