# Tagged Questions

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

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### acceleration and time dilation

Is it true that a freely-falling body accelerates because, as time slows toward the center of the earth, each second is longer than the preceding one, giving the body further to travel? A simple yes ...
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### Difference between classic velocity and spatial velocity [closed]

I am reading a tutorial about a physics simulator I am using, and it has the following code (in C++, but not important): ...
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### Does deformation due to a force affect the acceleration produced by it? [closed]

You have two same masses, one non-deformable and the other plastically deformable. You exert the same force for same time. Will they move with the same speed? Obviously the one will deform and move, ...
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### What is the intuition behind this acceleration formula?

What is the intuition behind this acceleration formula? In another word, how to demonstrate this by using common sense without using chain rule?
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### Accelerating antielectrons [closed]

I just signed up to the site. I am not a physicist, but I find physics fascinating. My understanding and knowledge is very little. I was doing some reading on Alpha collaboration < http://socrates....
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### Gravity, Acceleration, Time Dilation and the Equivalence Principle

Three clocks are started at exactly the same time on Earth. The first and second clocks are taken into the vacuum of space. The first clock accelerates until it reaches 100,000m/s, then stays at this ...
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### Can empty space be a frame of reference to measure velocity?

I am wondering if there is only one object in the universe than does it make any sense to talk about its velocity. If empty space can be thought of as a reference to measure its velocity than it might....
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### Doubts About Force and Inertia!

But then what does inertia mean at all!? Cant we calculate how much it resists the applied force? I mean considering an imaginary plane with no friction but gravity as of Earth and an enormous mass of ...
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### What's the formula for the speed of an accelerating car?

I am trying to find a formula that closely describes the speed of an accelerating car over time. I have found many graphs on the internet, but so far no formulae to generate them. For my purposes I ...
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### How to interpret the equation of motion of a point that changes its acceleration

I'm trying to understand more deeply the equations of motion for a constantly accelerated 1D motion. Consider a point that moves with constant acceleration $a$ and that, at a certain moment $\tau$ ...
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### Relationship $v_A^2-v_B^2=2a_t\Delta s$ for motion with constant tangential acceleration [closed]

I can not understand a relationship in the general motion in the plane. I am considering a point, which follows a curved trajectory. Indicate A and B two different position of the trajectory and $v_A$ ...
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### How to find tangential and normal unit vector to a trajectory from the equation? [duplicate]

Considering a 2D motion in a plane and the equation of the trajectory of a point $y=f(x)$, I don't understand how exactly $\frac{\mathrm{d}y}{\mathrm{d}x}$ can be used. In particular if I'm looking ...
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### Acceleration in a non-inertial reference frame

I have a conceptual doubt on the relation about the acceleration in a non inertial system. To explain the doubt without misunderstanding, I'm going to write the text of an exercise: A platform ...
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### (+)/(-) Acceleration & (+)(-) Velocity

Does a negative acceleration mean an object is slowing down? Does a negative velocity basically mean you are moving at an opposite direction? The sign is just direction?
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### Ball Bounce Acceleration at the Point of Bounce [closed]

simple question but I wanted to confirm my approach of thinking about the problem. Question: A rubber ball is dropped from the fifth story of a building and free falls to the ground, after which ...
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### Second order Fermi mechanism. Is there a mistake in the Claus Grupen book?

The second order Fermi mechanism describes the interaction of charged particles with magnetic clouds. This model leads to a collision-less acceleration of cosmic rays up to ultra high energies. A ...
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### Measuring force of a punch

I'm trying to build a device that can mesure the force of a punch. ​ My initial plan was to build a platform with 4 springs (one at each corner) and an accelerometer in the middle. But, if the ...
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### What orientation will let me drive the fastest with a tray of coffee on the floor? [closed]

I like coffee. I like to drive fast. These two don't usually go together, unless you like that coffee all over your floor because you tipped it over going around the corner. If I have up to four cups ...
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### How many neutrinos would it take to accelerate a 75kg human? [closed]

Assume that you have somehow creates a neutrino emitter that does not release any heat or light–just a lot of neutrinos. You weigh 75kg, and step right into the flow of the emitter. How many ...
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### Velocity change with height

The formula $v^2 = u^2+2GS$(where $v$ is final velocity, $u$ is initial velocity, $G$ is acceleration due to gravity and $S$ is the linear displacement) assumes that gravity remains constant ...
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### Acceleration of bodies

Whenever when there is collision or when there is continued movement during contact we assume there is only continued acceleration and no other type of motion. We use this assumption to find various ...
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### Given a current velocity and a fixed input energy, how much faster will a relativistic particle be?

The relativistic kinetic energy of a particle with mass $m$ and velocity $v_0$ is $$m c^2 (\gamma_0 - 1) \textrm{ where } \gamma_0 = \frac{1}{\sqrt{1 - \frac{v_0^2}{c^2}}}$$ I would like to know how ...
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### Needed acceleration input to reach a target point

I have a point mass traveling on a 2D plane with some initial velocity v and initial position r. The point mass is able to ...
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### Gravitational Time Dilation vs Acceleration Time Dilation

I might be a little dense to this subject, but I would like to ask a question relating to this one ( Is gravitational time dilation different from other forms of time dilation? ) but asking if this ...
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### What Would One Observe of a Calendar on Earth, Given a Round Trip to Another Star and back?

I want to ask a clarifying series of questions on what I think is a relatively simple scenario. It's a long one but I've tried to word it as simply as I can manage while trying to do the question ...
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### Trouble with Simple Average Velocity [closed]

I have a super simple question on average velocity that either I am not setting up correctly, or is itself graded incorrectly in a huge online system used by thousands of students for a very long time....
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### Acceleration of log moving without slipping with/under a plank

So I have this image: I know how to solve the accompanying physics problem once I have determined the relative accelerations of the logs and the plank. According to my physics textbook, the cm of ...
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### Calculating the theoretical velocity of a projectile

Recently, I made a homemade air powered airsoft gun. I wanted to know how fast it would accelerate out of the barrel, so I tried do do some calculations, but to no avail (keep in mind, I haven't taken ...
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### Maximum possible acceleration value on a ball in volleyball game

I have been examining this subject on web but could found enough information yet. I have to make a decision on choosing "range" for accelerometer which will measure acceleration value of ball in ...
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### Acceleration in a space capsule which is falling to the earth [closed]

At first I apologize for asking such a career killing question in such an elite platform. Today I tried to prove something to four graduated engineers which I will mention below. The argument ...
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### In perfect vacuum (no external force), if I apply a small amount of force to a body, will it continue to accelerate forever?

According to the equation $F = ma$, the greater the force applied to a body, the greater its acceleration. But in a place where there is no gravity or any other kind of external force, if I apply a ...
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### Why the distance equation is not working while calculating distance manually?

I was wondering how the average velocity is the arithmetic mean of initial velocity and final velocity if acceleration is constant. So, my first part of the question: Can someone give me an algebraic ...
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### Acceleration of a static observer in Schwarzschild measured in locally inertial frame [closed]

Consider a static observer at $r=R>2M$ with four velocity given by $$U^\mu=\frac{dx^\mu}{d\tau}=(1-\frac{2M}{R})^{-1/2}\delta^\mu_0$$ in the Schwarzschild metric ds^2=-(1-\frac{2M}{r})dt^2+(1-\...
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### Can the single object accelerate? (Relativity theory) [closed]

Suppose space is empty except for one single object. According to relativity theory it doesn't matter whether we assign a constant velocity to it or not; in both scenarios the same is predicted. The ...
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### How do you determine how much does an object accelerate by gravity [closed]

Ok, so say i have an object that has a mass of 1kg and it "pulled" by a planet, i know the F = GmM/r^2 thing, but it gives newtons. How do i know how much the object accelerates towards the planet in ...
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### What force causes the ball to move up?

Let's consider this super-simple example. The ball (mass $m$) is moving from position 1 to position 2 at constant horizontal velocity $v$ until the ball reaches the red arrow (in position 1, it has ...
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### Finding acceleration using components method

The problem I am working on gives me an initial velocity of 2[E15N] m/s and a final velocity of 4[E35N] m/s after 30s. I need to find acceleration so I create a right angle triange for both of these ...
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### Speed Calculater [closed]

I want to make an android calculator which can calculate speed of a vehicle by using mobile sensors(accelerometer or GPS) i am interested to calculate it by using accelerometer instead of GPS is it ...
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### Question about acceleration & deceleration in real world?

have searched the net and am not satisfied with any answer I have found to calculate the following:- Here is an example just for reference. Suppose I can accelerate my car from 0-100km/h in 10s. That ...
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### fortune wheel - angular acceleration, given initial velocity, radius, angle

I have another physics problem and I'm trying to solve this using formulas I found on the web. I'm an online student and there is no textbook given for our course nor is the topic explained in the ...
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### Can there be acceleration without velocity?

If I was in a spaceship continually accelerating at $9.81m/s^2 =1g$ in a straight line, I would reach near light speed within a year. On Earth, we are in a gravitational field of $1g$, which ...
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### motion with constant acceleration question! [closed]

Consider a motorboat maneuvering on the surface of a lake, Is it possible for the boat to have accelerated motion in the x axis and unaccelerated motion in y direction?
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### Does it take a larger force to stop a faster object?

Does it take a larger force to stop a car that is moving at a velocity 2*v than if it is moving at a velocity v? I'm confused as the force required to decelerate a car depends on the mass and the ...
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### When is a circle not a circle?

Imagine a 2D uniform circular motion of constant magnitude but changing direction in an area of zero g. The forces will be equal all the way round - it will be a perfect circle. Now imagine the same ...
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### Velocity of particle constant under null initial magnetic force

I have got a doubt on the exact application of Newton's first, and third, law. Let us for example suppose that a particle, electrically charged with charge $q$, is moving at the instant $t=0$ with ...
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### Acceleration in Space

Lets assume a body with a certain mass is in a region of space that has zero $g$ (or pretty close to zero $g$). Would acceleration in a straight line produce $g$-forces? Would that mass acquire ...
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### How can I prove that the covariant acceleration is normal to the velocity?

I'm trying to show that the covariant acceleration is normal to the velocity for a massive particle. I think that I understand why this has to happen because I understand the covariant acceleration as ...
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### Length Contraction and Acceleration [duplicate]

Say that I have a spaceship that needs to travel 490 lightyears to the exoplanet Kepler 186f. Half the way of the trip the spaceship accelerates with a constant acceleration of 1G and on the other ...
Humans can survive maybe 3-10 $g$'s sustained acceleration when applied to their backs, like in a rocket launch. This question is not about that. I'm wondering about alternative theoretical future ...