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

learn more… | top users | synonyms

7
votes
5answers
243 views

Rapid (ac/de)celeration in relativity does what to inertial clocks?

EDIT (to clarify my question): I think some of the answers here are accounting for light travel time and telling me what I'd actually see on Earth's clock, so I've edited my first paragraph to ...
2
votes
1answer
39 views

How to get speed of a train without using GPS

How can I measure instantaneous speed of a train in which I am travelling without using GPS/location services? The train can start underground or can start from ground level (where GPS is available) ...
2
votes
2answers
62 views

Why was it difficult to walk in the same direction the train's acceleration, and easier the other way around?

The other day while I was walking in the same direction that the train was accelerating. Then I came across this question. Please if would answer it, I am very curious to know. But when I walked the ...
1
vote
3answers
51 views

Charge moved across a potential difference; where does the energy for emitted radiation come from?

Let's use an electron and a 1V potential difference as a mode. In school I learned that if the electron is at the negative end of the electric field, its potential energy is equal to the work that ...
0
votes
0answers
31 views

What is the equation for the position of a falling body as a function of time? [duplicate]

I know that near the surface of the earth a projectile's position follows a parabolic curve in function of time because the acceleration is constant (about 9.8 m/s2). However, acceleration ...
1
vote
2answers
46 views

Simple harmonic motion..direction of acceleration

To solve questions about simple harmonic motion, my book says $\ddot{x}$ (i.e. acceleration) is in the direction of increasing $x$, i.e. away from equilibrium. I don't understand why is this so, since ...
1
vote
1answer
21 views

Distance formula using initial velocity and acceleration

we know $S=ut+1/2at^2$. Now lets say my initial velocity $u=10m/s$ and acceleration be $a=5m/s^2$. In first second distance traveled $S^{_t=1}=10m$ as my speed is $10m/s$ and time is $1s$. In next ...
1
vote
2answers
91 views

Forces on wheels in an accelerating vehicle

Assume that a motorcycle of mass $m$ has two wheels that are equidistant from its centre i.e the force on each wheel is $mg/2$. If the motorcycle accelerates forward, will the two forces on each ...
0
votes
2answers
45 views

Regarding Basic laws of motion

When a constant force is applied on body which is free to slide on a surface, does it move with a constant velocity after some time or does the velocity keep on increasing? Please explain it for both ...
1
vote
2answers
27 views

Practical limit of equivalence principle

The equivalence principle says, for a small elevator, it is not possible to distinguish between a closed elevator moving at a constant acceleration, and the same amount of gravitational acceleration ...
5
votes
2answers
203 views

How does light change directions? [duplicate]

To the best of my knowledge, light will always travel at the speed of light. How then does it get reflected and change directions? Wouldn't it have to decelerate, come to a stop, and then accelerate ...
1
vote
0answers
15 views

Acceleration Absolute from all Non-Accelerating Frame of references

Is Acceleration Absolute from all Non-Accelerating Frame of references? Though experiment: Imagine cars on a two-way highway travelling at different velocities. A motorbike is accelerating at A'. From ...
1
vote
0answers
29 views

Analogy Between Momentum and Faraday's Law of Induction

What is the reason behind momentum, during acceleration? Mass resist velocity change during acceleration similar to Coiled wire resisting Current amount change. The similarity is worth looking at. ...
0
votes
2answers
43 views

An object is accelerating on a rough surface with frictional force of 10N. Is the friction doing any work on the object?

This question might look stupid to some but I am in great confusion. An object, say a box, is moving on a surface with some velocity v and is accelerating. It means that the force applied by the box ...
1
vote
4answers
88 views

When is tension positive?

A 5kg mass is hanging from the roof of an elevator accelerating downward at a speed of 1.65 m/s^2 what is the tension of the string (ignore friction, string mass, and air resistance) ? I used this ...
0
votes
2answers
53 views

One dimensional motion - Why does a ball fall back in my hands when I throw it up in a moving bus? [duplicate]

Suppose you are moving in a bus and you throw a ball upwards. Why does it always land in your hand and does not fall behind you? The bus is moving with a uniform velocity in a straight direction. Now ...
0
votes
1answer
44 views

Does light accelerate as it nears a black hole? [duplicate]

As light is affected by gravity ( gravitational lending and black holes), it would seem that gravity causes acceleration. Acceleration has two parts: direction and magnitude. It is clearly evident ...
0
votes
3answers
59 views

Calculate acceleration based on differential pressures

In my example, water is in a tube and is being accelerated by a compressed air. I already know that $P = \frac{F}{A}$ so if you know the pressure and you know the surface area its acting on, you can ...
1
vote
1answer
163 views

What is the difference between gravitational force and gravitational field?

I see two different formulas describing gravity: $$F=\frac{GMm}{r^{2}}$$ $$g=\frac{F}{m}$$ But I don't understand the difference between gravity as a force and its field as a vector.
6
votes
5answers
300 views

How does constant thrust avoid quadratic kinetic energy accumulation?

I haven't found the right search terms for this question, so if it has been answered, references would be welcome. Suppose we start from experimental station in deep space (interstellar space if need ...
2
votes
4answers
69 views

Why do heavier objects provide more reaction force?

According to Newton's third law, to each action there is an equal and opposite reaction, which means that no matter how heavy is the object, if I give it X amount of force, it will give that force ...
1
vote
0answers
29 views

Simple harmonic motion in a horizontally accelerating lift [duplicate]

How would the time period of a pendulum in a lift be if the lift was accelerating horizontally to the right ? My teacher did it by putting a pseudo force "ma" to the left, then getting the resultant ...
-1
votes
1answer
63 views

How does Newton's third law work

This law states that to each action there is an opposite and equal reaction. and I understand that this is the law that Rocket thrusters are built on. they use the combustion of fuel to push out hot ...
-1
votes
1answer
55 views

Displacement on a turn with constant speed with a pitfall

A car is driving North-West on a highway. It has a speed of $20 $ m/s with the cruise control on. Ten seconds later, the car is heading North-East (still going $20 $ m/s). Determine the ...
1
vote
4answers
89 views

Gravity and force

I have a question and am not able to answer it. Suppose you drop two objects from different heights. They are exactly the same shape, size and weight. Now we know that the gravitational acceleration ...
1
vote
2answers
74 views

Tension of a string rotating a ball in a circular motion?

A ball of mass 5kg is attached to a string of length 120 cm and rotating vertically at a speed of 10 cm/s. what is the tension of the string when the ball is farthest to the right from the ...
0
votes
2answers
62 views

The relation between acceleration and inertial force

Acceleration causes inertial force, and it is not relative, but why? What is the reason for feeling inertial force by acceleration?
0
votes
2answers
72 views

What is total acceleration?

I'm currently taking a Physics class and we are studying motion in a circular path. and i'm kind of fuzzy on what the total acceleration actually is. take this problem for example An automobile ...
0
votes
2answers
40 views

Using constant snap, what acceleration is required to achieve a desired change in position, with acceleration and velocity bounded

Also assuming you must approach the bounds of acceleration and velocity smoothly -- i.e. their derivatives approach zero as you reach the bounding value. In some cases, you may not reach the bounds ...
1
vote
0answers
46 views

Applications on Newtons' laws [closed]

A light string passes over a smooth pulley and carries at one of its ends a body of mass 90 grams and it carries a body of mass 50 grams at its other end.the system started its motion from rest when ...
1
vote
1answer
35 views

Calculating mobile displacement based on acceleration

I have written a mobile app that measures x y z accelerations. I am trying to convert the acceleration results into displacement but dont think a simple $d=\frac 1 2 {a {t^2}}$ will do the job. We ...
1
vote
2answers
53 views

Accelerating potential

Will an accelerating potential accelerate a neutral atom? For example, consider an atom of hydrogen subjected to an accelerating potential of $V$. As the kinetic energy of a particle accelerated by a ...
0
votes
1answer
55 views

Calculating Potential Energy

I'm familiar with the potential energy equation, but I'm concerned with the value of 'g' in it. I know that, at sea level, earth's gravitational acceleration is 9.81 m/s/s. So I know that within the ...
0
votes
0answers
28 views

Pitch / Roll compensation on vertical acceleration (IMU)

Hello i'm working on the calculation of wave height based on acceleration movement on vertical axis Z provided by an accelerometer (Razor 9 DOF sparkfun). I know how to calculate the wave height when ...
-1
votes
1answer
46 views

Acceleration needed to make a solid turn into gas? [closed]

There's a joke in a show in France where it is said speaking of a human that he would turn into gas if accelerated enough. My questions : Is this possible without friction ? What would be this ...
1
vote
0answers
26 views

Acceleration 4-vector in Schwarzschild metric [closed]

I am working on A note of a paradoxical property of the Schwarzschild solution by Abramowicz M. A. and Lasota J-P It is a note on surprising cases in the context of the standard Schwarzschild ...
2
votes
2answers
144 views

What is the Benefit of Plotting a Log of Net Force vs. Log of Acceleration Graph?

In preparation for a quiz, I've been going over a set of sample questions. One question in particular asks that if I am to graph the logarithm of the horizontal net force of a system vs the ...
0
votes
1answer
84 views

Calculating stopping distance of a car on a slope

I'm having trouble setting up a homework problem properly. We are given the following: A given car can brake to a stop from a speed of 60.0 mi/h in a distance of 123 ft on a level roadway. What ...
0
votes
0answers
18 views

Energy losses of a ball, hitting the ground due to elastic and accelerating processes

There is a question about gravitational force and irreversibility. In my answer I pointed towards the phenomenon of photon emission during accelerations and by this of energy loss. My last sentence ...
4
votes
2answers
59 views

Acceleration of a car on Earth and on the Moon

Suppposing the same enviroment conditions and without considering the air friction a car at the start of a race would have a greater acceleration on Earth or on the Moon, or would the accelerations be ...
1
vote
1answer
38 views

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 ...
1
vote
1answer
74 views

Difference between classic velocity and spatial velocity

I am reading a tutorial about a physics simulator I am using, and it has the following code (in C++, but not important): ...
2
votes
1answer
45 views

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, ...
0
votes
1answer
38 views

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?
1
vote
0answers
29 views

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 < ...
0
votes
1answer
44 views

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 ...
1
vote
1answer
55 views

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 ...
0
votes
1answer
39 views

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 ...
-2
votes
1answer
77 views

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 ...
0
votes
2answers
47 views

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 $\tau$ ...