Skip to main content

Questions tagged [velocity]

The time rate of change of the position of an object

Filter by
Sorted by
Tagged with
0 votes
1 answer
48 views

Is the answer given in the option wrong? [closed]

The question is "An Object moves along a straight line. The graph illustrates how the acceleration of the object changes with time. The direction of the motion of the object changed only once, ...
Praveen Kumaran P's user avatar
0 votes
2 answers
126 views

Doppler shift from a moving reflector and source if only the relative velocity is known?

Suppose there is a device which is producing and listening to sound (sonar), a reflector is moving with respect to device and the velocity of reflector and device with respect to the air is not known, ...
Pradyuman's user avatar
  • 866
0 votes
0 answers
28 views

Interpretation of a motion in continuum mechanics with a spatial description

in the book introduction to continuum mechanics 4th edition (Michael Lai, second chapter), there is an exercice about a motion of a continuum (exercice 3.2.1). the motion is $$x1 = X1 + k.t.X2 ;$$ $$...
christian's user avatar
2 votes
1 answer
76 views

How to properly combine kinetic and gravitational time dilation effect?

I developed a time dilation calculator that includes both kinetic (Lorentz Factor) and gravitational (Schwarzschild Metric Formula) factors to assess the time difference between Earth and satellites. ...
Eliot Mallamo's user avatar
0 votes
1 answer
29 views

How does the direction of the change in momentum of the object change during the motion?

In the case of an object's movement resembled in this graph, as the gradient is decreasing, a decrease in velocity occurs. According to the formula $$p = mv$$, The momentum is directly proportional to ...
Mohammad Osama's user avatar
0 votes
1 answer
33 views

When does magnetic force affect the velocity of a charged particle

So according to this para, I understand that since one component of velocity is perpendicular to magnetic force (and parallel to magnetic field) that component will not change. But other component is ...
android's user avatar
  • 91
1 vote
2 answers
54 views

Newton's laws on constant velocity [duplicate]

We know that Newton's second law tells us $F=ma+v\frac{dm}{dt}$ so, if a body has a constant velocity but a changing mass, then the equation tells us that the net force acting on the body is $F=v\frac{...
Avineet Mohapatra's user avatar
0 votes
1 answer
35 views

Friction acting on a moving car

I am trying to understand the nature and direction of friction force acting on from the ground a car driving up an incline. I was thinking about a simple situation where a car of mass $ m $ is driving ...
Lukasz Skowron's user avatar
0 votes
2 answers
66 views

How many $G$ of accelaration do we experience when we come to a flat surface from a slope?

I was recently riding a bicycle when I realised that when I went onto a flat road from a short but steep slope, I felt something weird in my body as if I was expereiencing some difference in the ...
Sambhav Khandelwal's user avatar
0 votes
2 answers
52 views

Does a block's velocity becomes zero when it hits a spring?

It says the velocity of the block becomes zero at the instant of maximum compression. But does it not go with a constant velocity as it's a smooth part? It should hit the spring and then oscillate for ...
android's user avatar
  • 91
0 votes
4 answers
87 views

What is the tangential component of any vector?

There's a statement I discovered in the book I am reading which says Kinetic energy changes only when speed changes and that happens when the resultant force has a tangential component. Does that ...
android's user avatar
  • 91
-1 votes
2 answers
65 views

Total momentum of a fluid in a pipe [closed]

Suppose we have a cylindrical pipe let's say length L = 10 m and radius R = 1 m through which water is flowing. The velocity distribution is given by Poiseuille's Law: $v(r)=\frac{\Delta P}{4L\eta}\...
Javieer Picazo's user avatar
2 votes
1 answer
58 views

Velocity Needed For Water To Overcome Adhesion Force To A Rounded Steel Inclined Plane

Context: I work at a fast food restaurant with a 3-module sink. The sides are slightly angled down to allow the water to trickle down into the compartments. I found that water clings to the side of ...
Rrasco88's user avatar
0 votes
2 answers
110 views

What is the science behind why when displacement is increased, so will the final velocity? [closed]

I'm writing a paper and need to write a hypothesis. I did an experiment using a weighted cart with a string and falling mass, and also a pulley. This was completed on a flat table onto the floor. In ...
dmull's user avatar
  • 1
0 votes
1 answer
63 views

Does QED explain why Moving charge produce magnetic field? [closed]

I wonder that moving charge produce magnetic fields. Now a days quantum field theory explain much of particle physics their underlying mediate particles. But can QED explain why moving charge produce ...
Sanket Thakkar's user avatar
0 votes
1 answer
13 views

Threshold velocity between the two models for fluid resistance/friction as a function of velocity?

My textbook says that there are main two equations that model the friction, f, of an object with speed, v, moving through a fluid: $$f = k*v$$ ("fluid resistance at low speed") and $$f = D*v^...
polimorphism's user avatar
0 votes
7 answers
94 views

How does the result of derivative become different from average ratio calculation?

Lets give an example. Velocity, $v=ds/dt$. If we know the value of $s$ (displacement) and $t$ (time), we can instantly find the value of $v$. But then this $v$ will be the average velocity. Now ...
Arafat's user avatar
  • 15
14 votes
7 answers
4k views

Why does a charge need to have a velocity to experience force in a magnetic field?

While studying magnetism, I learned that force on a charged particle inside a magnetic field is $$\mathbf{F}=q(\mathbf{v}\times\mathbf{B})$$ where all symbols have their usual meaning, which implies ...
Advait K's user avatar
  • 161
0 votes
5 answers
92 views

Motion formula gives correct answer but without formula gives wrong answer [duplicate]

Assume a body with initial velocity= 10 ms final velocity= 20 ms and acceleration= 2 ms , so the time to reach final velocity will be 5 seconds. If we try to find distance it will travel in 5 seconds ...
nitu sahay's user avatar
0 votes
1 answer
43 views

Why is velocity proportional to radius in a spherical explosion?

While doing problems on spherically symmetric explosions, I noticed I had been intuitively assuming that velocity scales linearly with radius of the "shell" under consideration. To be more ...
Cognoscenti's user avatar
14 votes
4 answers
2k views

Why doesn't constant acceleration give me total displacement?

I started learning 1D kinematics and learnt definitions of constant velocity and constant acceleration. I thought that if a particle is changing its velocity uniformly then it has constant ...
Sai Varun 's user avatar
1 vote
2 answers
41 views

Setting $u$ = escape velocity when calculating the maximum height of a thrown object

So, if I throw an object at some velocity $v$ at an angle θ, the maximum height reached by the object is $\frac{v^2\sin^2{\theta}}{2g}$ but, I know this isnt true. clearly in a weird way, the height ...
uggupuggu's user avatar
  • 129
1 vote
2 answers
114 views

This model of friction implies the speed decays exponentially, but shouldn't it actually vanish within a finite amount of time?

A snooker player strikes the cue ball, so that it starts moving with constant speed $v_{0}$. We assume that spin plays no role in its motion. Due to friction between the ball and the cloth of the ...
M. Wind's user avatar
  • 743
0 votes
3 answers
71 views

How do mass and velocity relate to momentum? [duplicate]

So this is more of a clarifying question. A lot of online definitions state that momentum is a measure of how hard it is to stop or swerve an object, which makes sense. However, the formula for ...
user386598's user avatar
0 votes
2 answers
88 views

Linear velocity on a circle

Consider a ball rotating around the z-axis with constant angular velocity $\vec{\omega}$, then the linear velocity $\vec{v}$ is given by $\vec{v} = \vec{\omega} \times \vec{r}$. It is easy to ...
Chuan Huang's user avatar
0 votes
1 answer
44 views

What is the physical significance of this generalised potential?

Consider a generalised potential of the form $U=-f\vec{v}\cdot\vec{r}$ where $f$ is a constant. This potential should not contribute any internal forces between particles as \begin{equation} \vec{F}=-\...
Rescy_'s user avatar
  • 838
18 votes
9 answers
8k views

Where does "excess" energy go when a vehicle uses a lower gear to move at a given speed?

So I understand that a lower gear as advantageous when accelerating a vehicle or when driving up hill (e.g because you are having to accelerate against gravity). I know this is because of the ...
OceanExplorer's user avatar
0 votes
1 answer
89 views

Is it possible to have a uniform speed but variable velocity in one-dimension motion?

Is it possible to have a uniform speed but variable velocity in one-dimension motion? I saw a lecture where teacher said that it is possible if particle changes its direction of motion 180$^\circ$. ...
NOTE Book's user avatar
1 vote
1 answer
49 views

Density of states - as a function of electron velocity

A condensed matter textbook states that in a 3D gas of electrons obeying the Fermi-Dirac statistics the number of electrons per unit volume having velocity components in the ranges $u, u+d u$, $v, v+d ...
Tomi's user avatar
  • 713
0 votes
4 answers
128 views

Why acceleration is not always parallel to velocity but velocity is always parallel to displacement? [closed]

Velocity is derivative of displacement : $$\vec v=\frac{\mathrm {d\vec r}}{\mathrm dt}$$ And acceleration is derivative of velocity. $$\vec a=\frac{\mathrm {d\vec v}}{\mathrm dt}$$ Given that their ...
An_Elephant's user avatar
-1 votes
2 answers
62 views

Why is velocity used for kinetic energy instead of speed? [duplicate]

This may seem like a self-explanatory question, but if kinetic energy is a scalar quantity, and squaring the velocity essentially removes its vector quality, why not use speed instead? I have a hunch ...
Ephemeralist's user avatar
0 votes
1 answer
148 views

How 'fundamental' is position?

From my knowledge, which is admittedly inadequate, it seems that in Classical Mechanics and other parts of physics, the integral of position isn't used at all. As in, one can easily imagine scenarios ...
OdinOblivion's user avatar
0 votes
1 answer
44 views

The locus of the velocity vectors of a boat navigating in the sea under the presence of a very strong wind?

I already asked a question very similar to this one here and I think the solution would not work when the boat navigates in the sea when a very strong wind blows. That is I am trying to find the ...
Majid's user avatar
  • 159
0 votes
1 answer
45 views

Bose-Einstein statistics: What would the average or expectation value of velocity $\langle v \rangle$ be for an ideal Bose gas?

I would appreciate if anyone could provide me with the general velocity distribution probability density function and compare the same with the Maxwell-Boltzmann velocity distribution.
Prashant Mishra's user avatar
1 vote
0 answers
54 views

Velocity of a body after rising out of a ideal liquid

Suppose you have a cube of volume $S m^3$ and you submerge the lower edge of the cube to a height $h$ below the surface of the liquid. $h>S$ i.e the cube is completely submerged. Now, once you ...
Kyathallous's user avatar
1 vote
1 answer
77 views

Why mean time between collisions has two formulas one with drift velocity and one with average speed?

Drift velocity is defined as : $$V_{dx}=\frac{e \tau}{m_e} E_x$$ Therefore, mean time between collisions is τ= $\frac{m*v(drift)}{eE} $ however, τ is also τ=$\frac{\Lambda}{<v>} $ in which $<...
olly's user avatar
  • 11
-4 votes
1 answer
40 views

In the formula for the conservation of mechanical energy, what does mean the velocity?

For example I have the formula: MEI=MEF mgh+mvi2/(2)=mgh+mvf2/(2), What does initial and final velocity mean?
asd20234's user avatar
0 votes
2 answers
65 views

How to calculate the final position of a particle under variable accelaration and its instantenous velocity?

I'm a first-semester physics student who was recently on a train. On a screen, it said the instantaneous velocity of the train was 176 km / h. We had 4 min left until our destination. I wanted to ...
jazzblaster's user avatar
0 votes
1 answer
69 views

Changing variables from $\dot{q}$ to $p$ in Lagrangian instead of Legendre Transformation

This question is motivated by a perceived incompleteness in the responses to this question, which asks why we can't just substitute $\dot{q}(p)$ into $L(q,\dot{q})$ to convert it to $L(q,p)$, which ...
user1247's user avatar
  • 7,408
0 votes
0 answers
23 views

Circle to Polygon & Circle to Circle Velocity Resolution

I current am working a 2d physics engine, but have recently hit some bumps in the road. Polygon to polygon collision and velocity resolution works without issue, but I am struggling to get working ...
TrippR's user avatar
  • 1
0 votes
1 answer
82 views

Statistical independence of $x,y,z$ dimensions for Maxwell velocity distribution function

I have been looking into the derivation of the Maxwell speed distribution function as for instance given in https://en.wikipedia.org/wiki/Maxwell%E2%80%93Boltzmann_distribution#...
Thomas's user avatar
  • 2,712
3 votes
3 answers
702 views

In this conservation of momentum problem, where is the sign error coming from?

Say I have a particle travelling in the $x$-direction and breaking into two pieces: Conservation of momentum in the $x$-direction obviously gives: $$mv = m_1 v_1 \cos(30) + m_2 v_2 \cos(60).\tag{1}$$ ...
Allure's user avatar
  • 21.4k
0 votes
1 answer
80 views

In $a = dv/dt$, is $a$ the net acceleration? [closed]

While going through the calculus approach to accelerate, we have, $$a = dv/dt, $$ I think, here, v and a should be in the same axis, is my process correct? in a planar motion in two dimensions, it ...
sachin's user avatar
  • 1
0 votes
1 answer
44 views

How does the distribution of floor choices of your co-passengers affect your time of arrival in an elevator?

Note: This is a wiki post. Suppose you are late for a meeting and you have to take an elevator. The floor choice of your fellow passengers influences how late you will reach your destination. If ...
AlphaLife's user avatar
  • 12.5k
1 vote
2 answers
127 views

Average velocity showing different results

I was solving a question, in which, a particle has travelled a distance $s$, with initial velocity $0$ and constant acceleration. So the equation of motion becomes, $$ v = a t \tag{1} $$ and $$ v = \...
Agent_A's user avatar
  • 56
-4 votes
4 answers
235 views

How does a seatbelt help in a car crash? [closed]

If you are in a car crash, you will likely have on a seatbelt because they are supposed to help you from getting injured/harmed. But, I don't think they are that much of a help. First of all, say you ...
Kellan Heerdegen's user avatar
1 vote
1 answer
36 views

Determining star position and velocity to deduce closest approach?

I am trying to replicate the results found for Gliese 710's closest approach of ~0.05 parsecs in 1.3 million years approximately. I thought that by plotting the sun at (0,0) and using the stars ra,dec,...
user2279603's user avatar
0 votes
2 answers
54 views

Magnitude of Acceleration Vector when Speed is Constant

If I observe a change in direction of velocity, but not in speed: What does the acceleration vector look like? I am confused! The difference vector between two vectors of equal length A has a ...
Sylvia's user avatar
  • 123
0 votes
4 answers
188 views

Why isn't the tangential velocity of circular motion zero?

Why is tangential velocity 2πr/T if the body's total displacement in the end of one revolution is zero?
D4NT3 tennyson's user avatar
0 votes
2 answers
81 views

Instantaneous speed x instantaneous velocity

Related to Distinguish between instantaneous speed and instantaneous velocity I understand that the average velocity is given by the displacement divided by the change in time, and it is a vector ...
Quiet_waters's user avatar

1
2 3 4 5
46