Questions tagged [vectors]

Geometric object with magnitude (length) and direction.

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What is the three dimensional generalisation of a conservative force?

I was studying about conservative forces from a physics book (NCERT, a standard Indian textbook) and came to a para which is as follows: A force is conservative if it can be derived from a scalar ...
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What's the meaning of the coordinates if we use a polar coordinate system?

In general, the coordinates of a vector are defined as the projections of it onto the coordinate axis. Moreover, in a polar coordinate system, the basis vectors $\hat e_\phi$, $\hat e_r$ depend on the ...
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Two equal masses are glued to a massless hoop of radius R. Find position vector and velocity? [closed]

Two equal masses are glued to a massless hoop of radius R that is free to rotate about its center in a vertical plane. The angle between the masses is 2*theta. Find position vector and velocity? For ...
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Please help me with this physics question, I am stuck with it. Thank you [closed]

This question is about mechanical engineering, pin frame problem. I am not getting the answer not even close to it.
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Meaning of normal acceleration?

acceleration means the rate of change in velocity (vector quantity) and the differentiation means to divide a certain quantity into small elements (i.e $dx$) as we do to find the acceleration at any ...
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Cross product and handeness

I'm having some difficulties understanding the cross product in a left-handed coordinate system. I want to compute $\hat{i} \times \hat{j}$ for both systems in the picture (the first one is right-...
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Invariant quantities? [duplicate]

Every phisical quantity is tensor quantity (special cases of tensors are vectors and scalars). There are transformation rules for tensors. For example for scalar quantity F transformation rule is F'(x'...
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How do I derive the formula for radial acceleration when there is no uniform circular motion? [duplicate]

My lecturer states that $a_r=\dfrac{v_t^2}{r}=\omega^2r$ where $v_t$ is tangential velocity, he also wrote that this is derived the same way that radial acceleration is derived in uniform circular ...
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3 Dimensional Law of Cosines? Magnetic Vector Potential Problem

I am working on a problem similar to one in my textbook - however, I am having an issue understanding the example. Can someone explain the formulas from this picture? I am confused about using the law ...
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What causes the block to move horizontally on a FIXED wedge

Questions: For a block kept on a FRICTIONLESS FIXED INCLINE the acceleration down the plane is g*sin(A) (A is the angle of inclination) this acceleration can be further said to have components in the ...
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Why do we neglect $\Delta t^2(\frac{d\vec{r}}{dt}\frac{d\vec{\hat{r}}}{dt})$ at Taylor Expansion?

I'm just started to Ankara University Physics Department two weeks ago. I have missed my 2 hours of PHY105 course that is the last week Wednesdey. The subject that i missed was Derivatives of Vectors. ...
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Vector in an inverted frame of reference using Euler's Angles

Having some issues regarding the Euler's angles. Following is the short description of them problem. In the first step, I determined the Euler's angles to invert my frame of reference that is X, Y ...
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A textbook problem on vectors [closed]

I am stuck on a textbook problem on vectors (a new topic for me). The problem given in my book says: A man can swim with a speed of 4 km/h in still water. How long does he take to cross a river 1 ...
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Velocity in circular motion, $v = r × \omega$ or $v = \omega × r$?

I know it might sound silly to ask, but is the relation between linear velocity and angular velocity of an object undergoing circular motion $v = r × \omega$ or $v = \omega × r$? I didn't notice it ...
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Transformation of a vector's components in a time-dependent transformation

I know how the contravariant and covariant components of a vector transform when the coordinate system is changed (⇒ the known relation between the old coordinate system and the new one, I multiply by ...
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What is the use of Subtracting velocity?

By adding two velocity's direction we get the direction the object has travelled. But what do we get when we subtract vectors?
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Angular velocity in curved space (2d manifold)

In 3d Euclidean geometry, the velocity of any point of a rigid body is given by the cross product between its angular velocity and the position vector which links the instantaneous rotation center to ...
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Determining the $z$-component of a force to maintain equilibrium?

I came across this problem in vector mechanics wherein I’m asked to determine the value of $d$ such that the tension in cables $AC$ and $AD$ is half the tension in $AB$. What I initially did was ...
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Why do forces follow the triangle law of vector addition? [duplicate]

Why do, when two force act on a point their result is third side of triangle formed by the component forces?
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What causes tangential acceleration

The body moves on a circular path and has both tangential as well as centripetal acceleration. Friction acts outward as shown in figure. If this friction exceeds mv²/r, then shouldn't the body just ...
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Why was the concept of velocity created? [closed]

Why do we use velocity instead of speed for different physics problems? I recognize how they are different but why use one over the other?
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Why there is no a vector quantity in $P=\sqrt{2mK.E}$

Personally, If I saw this law I would say that momentum is a scalar quantity, because I know that (scalar quantity X scalar quantity = scalar quantity). Since momentum is a vector quantity, So why ...
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Proof of skewsymmetry of electromagntic function in Minkowski spacetime

I have been studying special relativity from the Gregory Naber's book: "The geometry of Minkowski spacetime" and I found a very strange proof. In Section 2.1, just before of equation 2.1.2. the book ...
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Why should forces add as vectors? [duplicate]

We are supposing in my mechanics course that forces add as vectors. But why, philosophically, should this be the case?
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We have a wire with cross-sectional area $A$, length $L$ and current $I$. If the wire is in a magnetic field $\vec B$, the magnetic force on each charge is $\vec F =q\vec v_d \times \vec B$. $\vec ... 1answer 52 views Consistent calculation of the total momentum in quantum physics When we are considering a one-dimensional case in quantum physics, we can calculate the momentum by solving the eigenvalue equation: $$-i \hbar \frac{d}{d x} \psi(x, t) = p_x \psi(x, t).$$ If we ... 2answers 72 views Calculating gravitational force with multiple planets [closed] I have a question regarding the following problem: Given the following system of planets (see image), calculate the total gravitational force acting on$m_3$. ($m_1 = 2 \cdot 10^{20}kg;m_2 = 1 \...
I'm following the text Introduction to Electrodynamics by Griffiths, and I came across the following in an in-text problem: Sketch the vector function v = $\frac{\boldsymbol{\hat{\mathbf{r}}}}{r^2}$...