Questions tagged [acceleration]
The rate of change of velocity of a body per unit of time.
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Forces to move a mass up and down and relation to potential energy
Basically the question is: Does it take the same forces to move a mass up or down including acceleration and deceleration?
The Newton second law: $F=m*a$ tend to say yes. In reality this is far from ...
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Determining how long it takes an object to reach a certain speed
Robotics related. On a linear servo driven rail one can typically set acceleration and maximum move speed. I am trying to determine the amount of seconds it takes the load to accelerate to a certain ...
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Reduction of a two-body problem into a one-body problem and Non-inertial frames
When a two-body problem consisting of two masses $m_1$ and $m_2$ is reduced to a one-body problem, the equation of motion for the particle of mass $m_2$ w.r.t that of mass $m_1$ is given by $$m_2\ddot{...
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Signification of not parallel force and acceleration vectors, in special relativity
the fact that acceleration and force vectors in special relativity are not parallel, is straight forward to derive. However, if we had to give a physical reasoning, argument behind this very ...
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How did concept of displacement emerge? [closed]
I think this question is very silly. This is what I thought of velocity.
In the attempt to define force and measure, it was observed that force can change the speed of the object and direction. It was ...
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1answer
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How to know which solution is physical?
When solving the expression for displacement of an accelerating object and solving for the time variable:
$$v_it+\frac{1}{2}at^2=d$$
$$v_it+\frac{1}{2}at^2-d=0$$
$$t=\frac{-v_i\pm \sqrt{v^2_i+2ad}}{a}$...
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1answer
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What is the weight of an object that accelerates upwards?
I belong to the aerospace community, and a basic concept among the people of this community is that an aircraft is called to be in 'steady flight' when the lift force balances out the weight of the ...
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1answer
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The centripetal force direction on hill and valley
A car is driven at constant speed over a circular hill and then into a
circular valley with the same radius. At the top of the hill the
normal force on the driver from the car seat is 0. The driver's ...
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2answers
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Can't wrap my head around the energy formula being half of mass times velocity squared [duplicate]
I'm trying to understand the "Why" of this equation but can't make sense of it, my intuition breaks down.
When I think intuitively of energy, I think of "How powerful the impact will be ...
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Why is tension negative in this question? [closed]
My question comes from part (b) of the question above. From part (a) I found that $\mu_f = 0.56$ no problem, but in part (b) in order to solve for $\mathbf{a}$ I came up with the system of equations $$...
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How long does it take to accelerate to 10$ms^{-1}$ using a 10W laser?
Given a laser of $P=10W$ and a space vessel of $100kg$, how long would it take to accelerate to a velocity of $10 m/s$ using the laser as propulsion?
My train of thought is that by using $E=Pt$ and $...
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Why does an object of constant velocity come to rest?
As far as I understand, friction is suppose to be present only when there's a force pulling an object forwards on a plane.
So, for example, an object would be lying on a horizontal plane; a force is ...
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1answer
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Clock speed changes due to centripetal acceleration
As far as I understand, the speed of your clock relative to other clocks is determined only by relative motion and by gravity differences.
Given a rotating sphere with 1 clock at the center, 1 at a ...
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1answer
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Has Rindler horizon already been tested experimentally?
For an accelerated frame, there is a Rindler horizon at a distance of $$X = \frac{c^2}{a}$$ where $a$ is the proper acceleration. For $a = g$ it is about 1 light year.
If one of that spacial ...
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2answers
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Layman question about relativistic acceleration
Alan is a hypothetical observer in a hypothetical spaceship accelerating at 1g. Alan would feel 1g of gravity because of his acceleration, and his speed will increase by apx 9.8m per second.
What ...
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Change in centripetal acceleration if tangential acceleration is non-zero
I recently read about circular motion. They showed that acceleration $\vec a$ of a object in circular motion is given by
$$\vec a = -\omega^2r\vec e_r + \frac{dv}{dt}\vec e_t$$
where $r$ is the radius,...
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1answer
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Is there something like acceleration constraint in a rigid body?
Suppose we have two points on a body which having acceleration a1 and a2 direction we know and magnitude as well , is there some sort of relation between them we can establish , like for velocities ...
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RN Black hole and an accelerated observer
If I use the spacetime geometry for the Reissner-Nordström case and try to see the black hole's effect on an accelerated charged observer nearby, can I use the covariant equation for a charge moving ...
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Why acceleration due to gravity same for two objects of different masses (neglecting air resistance)? [duplicate]
If a feather ball and bowling ball are thrown , both reach the ground at the same time. (neglecting air resistance)
The reason given to this is that
Both the bodies have same acceleration .
My ...
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4answers
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How does existence of graviton helps explain 2 different objects fall at the same rate?
Actually I want to see how gravitons help to explain why a feather and a bowling ball would fall at the same rate towards the ground assuming no air resistance, I would imagine bowling ball to emit ...
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2answers
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Can a body do SHM (Simple Harmonic Motion) without a force acting on it?
I thought that if we take a body which is performing Simple Harmonic Motion and take its reflection on a wall. Now we observe the reflection on the wall and so we can say the reflection is performing ...
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Calculating 2D acceleration vector direction to most quickly reach a point
I am currently writing a game where you fly a starship in 2D space. In a given timestep, the ship has the ability to accelerate at constant rate in any direction. The player can specify a point at ...
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1answer
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Does power consumption vary over time as a projectile travels down the barrel of a rail gun?
My assumptions (possibly incorrect) for a rail gun are that are that the mass of the projectile is constant, the current through the armature is constant, and the magnetic field strength along the ...
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2answers
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Has anyone directly observed the equivalence of inertial and gravitational mass for the electromagnetic force?
Before someone tells me to drop a bowling ball and feather off the Leaning Tower of Pisa in a vacuum, let me point out that, in general relativity, you can't deduce anything about either mass of a ...
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Instataneous acceleration where velocity vs. time graph is not differentiable?
In the diagram below, what is the instantaneous acceleration at t=30s? There's a kink in the graph at that point; so in my opinion the instantaneous acceleration is undefined. Any thoughts ...
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1answer
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Radial component of acceleration in simple pendulum
I have a slight issue with the simple pendulum problem. mathematically, the equations make complete sense, but, when i look at the problem in more intuitive manner, i get the following issue. in an ...
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How many particles can a cyclotron accelerate per accelerating cycle?
What is the limit for how many particles can be accelerated in a batch per one accelerating cycle by a cyclotron /size of gap between D's?/?
I've found simillar question - the answer was refering to ...
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How to determine velocity given 1D relativistic acceleration? [duplicate]
Assume someone can accelerate at $9.8 \frac{m}{s^2}$, or 1g, from their perspective, indefinitely (in a single direction). I want to compute how long it would take them to reach a given velocity from ...
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2answers
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Confusing crash course average velocity equation
I was watching crash course physics #1 and saw an equation (7:30) states that average velocity = initial velocity + acceleration*time. I could not figure out why this is possible and doesn’t the ...
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1answer
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How to derive gravitational acceleration from lapse function in General Relativity?
The lapse function in General Relativity for Schwarzschild space-time is defined as
$$\frac{d\tau}{dt}\equiv\alpha=(-g_{00})^{1/2}=(1-2/r)^{1/2},$$
where $\alpha$ is the lapse function. In Thorne et ...
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Can a particle make a turn in space without accelerating? Does the size of the turn it makes, make a difference?
Is it possible for a particle to have angular velocity but no angular acceleration? Even if the angular velocity does not change, does there always need to be a centripetal / centrifugal acceleration ...
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Angular acceleration related to a time dependent rotation matrix $R(t)$
Let the orientation of a coordinate frame $\{b\}$ w.r.t. a static coordinate frame $\{a\}$ be expressed by a rotation matrix $R_{ab}\in SO(3)$ whose columns represent the coordinates of the unitary ...
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Oscillation of a pendulum near a black hole
I'd like to compare the oscillation period of a mechanical pendulum hovering near the event horizon of a solar-mass black hole to an identical pendulum at the surface of Earth. Does the pendulum near ...
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1answer
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Radially Accelerated Observers on Schwarzschild Spacetime
I'll first provide a little bit of context, and then proceed to the question. Feel free to jump ahead to the question if you feel so, I'll try to keep all the absolutely essential information over ...
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1answer
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Is every frame in which Newton's third law is verified a non-inertial frame?
In this question How can a person inside from a veiled and free-falling elevator distinguish whether he is in an inertial or non-inertial frame?, Dale answered:
Within the frame of the free falling ...
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How can a person inside from a veiled and free-falling elevator distinguish whether he is in an inertial or non-inertial frame?
From wikipedia: "A non-inertial reference frame is a frame of reference that undergoes acceleration with respect to an inertial frame", according to that statement, I would say that an ...
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Is the sensation of apparent acceleration within the frame or visible force source enough to know if that frame is non-inertial?
In Renato Brito's book Fundamentals of Mechanics, a property of the non-inertial frame is defined as follows:
Non-inertial referential is any one that presents acceleration in relation to an inertial ...
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Proof of $a = v^2/r$ using similar triangles
The book states that the ‘change in velocity’ triangle and the displacement triangle has the same angle theta.
But I don’t get it? How can we prove that the two triangles will have the same angle?
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Need review for the following claims regarding Relativity
So me and one of my friend is having heated debate over validity of General relativity and special relativity. The following claims, I having hard time to understand, are they correct or not as ...
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4answers
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How does torque even work on intuitive level? [closed]
I just watched some videos on torque, and that created confusion in me.
What exactly is torque?!
Some people say it is the rotational equivalent of a force, but the units do not match out. Some say ...
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6answers
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Force acting on spring
From newton's 2nd law,we know net force=$ma$. Now since in ideal cases,springs are massless,force on spring should be $ma=0\times a=0$. But still forces like restoring force,weight of a body hanging ...
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Question about third Newton's law applied to nuclear fission
My question is about the energy that is gained by fission of Uranium 235.Suppose we have a box opened on one side where the radiation is emitted...so if that side looks to the sky that box should be ...
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4answers
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Why do object accelerate towards the Earth in general relativity?
In general relativity something in free fall, that appear to accelerate towards the earth, is actually not accelerating at all but moving along a geodesic so why does it appear that it is accelerating ...
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1answer
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Acceleration equation for the geodesic deviation equation
Defining a family of geodesics by $\gamma_s$, parametrized by the affine parameter $t$, the coordinates are defined by $x^{\alpha}(s,t)$. The vector tangent to the geodesics is defined as $u^{\alpha} =...
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Do Einstein's two postulates allow for handling acceleration in special relativity or is something else needed?
When I was taught special relativity, we started with Einstein's two postulates and worked from there. However we were also taught that a proper resolution of the twin paradox required general ...
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What is the intuition behind excluding the effect of gravity from accelerometer data
In the unit of accelerometer and linear acceleration, I see that accelerometer is angular and the linear acceleration is linear. There is the impact of gravity on the accelerometer. However, ...
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If $\mathbf{F}_{net} = m\mathbf{a}$ then how is $m\mathbf{a}$ not a force? [duplicate]
The question is in the title: If Newton's second law says that the sum of the forces acting on a body in a given direction is the same as the mass of the object times its acceleration in that ...
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2answers
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Net force on a mass when a string (massless) is cut
In the below given figure, $m_1 = 5$ kg and $m_2 =2$ kg and $F=1$ N. We have to find the acceleration of the either block and also find with what acceleration will $m_1$ fall after the string breaks ...
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2answers
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Pseudoforces as seen by observer in a non-inertial frame
Suppose, we have a car, that is accelerating with respect to an inertial frame, with an acceleration $a_c$. So, observers in the inertial frame can claim that there is a force $F_c=ma_c$ acting on the ...
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3answers
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Spacetime effects on human scale objects?
For a human standing upright on the earth, gravity would have a different value at the feet than at the head, and gravity influences the flow of time. Does the difference in the flow of time cause any ...
