Tagged Questions
0
votes
1answer
40 views
Relative Velocity problem
I was solving many problems on relative velocity and observed that when the question asks,
"what is the minimum time taken by the boat/man to cross the river.?"
so the solution says that he ...
0
votes
0answers
28 views
Assume the following vectors [closed]
Assume the following vectors:
$a = \frac{1}{\sqrt{2}} [0,1,1]$ and
$b = [1,2,3]$.
(a) Calculate the scalar product c = a c b
(b) Calculate the value of vector d where d = b - ca
(c) What is the ...
4
votes
2answers
111 views
Vector potential
I have difficulty understanding the following vector calculus example. Text can be found here. It is the 5th Q&A -- starting with equation (31.1035).It concerns finding the vector potential of a ...
-1
votes
1answer
57 views
man walking in rain:relative velocity
A man walking in rain at a speed of 3kmph find rain to be falling vertically. When he increases his speed to 6 kmph, he finds rain meeting him at an angle of 45 deg to the vertical. What is the speed ...
1
vote
1answer
27 views
Asking about centrepetal acceleration
please look at the fig first
1) How can you claim that the triangle ABC is same as the triangle PQR?
2) How can you claim that the angle between V1 and V2 is same as the angle between AC and AB?
...
3
votes
2answers
67 views
Sign of acceleration
I'm developing an application using accelerometer sensor. I'm not good at physics so forgive me if the question is trivial. If I have 3 values of acceleration: $x$, $y$, $z$, I find acceleration ...
1
vote
1answer
29 views
How to add magnitude data in an ENU coordiante system
I have water velocity data taken in an ENU (East, North, UP) or XYZ coordinate system. The data is contained in 3 columns like this:
...
0
votes
1answer
88 views
Component of force field tangent to a curve
I recently had to solve the following problem:
A force $F=10\hat x- 8\hat y$ is applied to an object that is constrained to travel towards increasing values of x along the path defined by $y=x^2$ ...
0
votes
1answer
60 views
Is it necessary to know initial y velocity to solve this projectile motion problem?
A marble is launched horizontally off a 93.0-cm high table causing the marble to land on the floor 1.85 m from the base of the table.
a.) How long was the ball in the air?
b.) With what ...
1
vote
0answers
75 views
Plane vector problem [closed]
Problem statement
A jet is flying at 600 mi/h in a direction of 450 North of West. 2.5
minutes later it is flying at 450 mi/h in a direction of 300 North of
East.
a) Sketch a vector ...
0
votes
1answer
143 views
Resultant vector problem
$\newcommand{\v}[1]{\vec #1}\newcommand{\i}{\hat i}\newcommand{\j}{\hat j}$
Problem statement (1,2)
A shopper at the supermarket follows the path indicated by vectors $\v A, \v B, \v C, \v D$ in ...
1
vote
2answers
101 views
Rotating a reference system on a vector
Assume you have a vector $\vec{x}=(\sin(\vartheta)\cos(\varphi),\sin(\vartheta)\sin(\varphi),\cos(\vartheta))$ given in spherical coordinates in a reference System "R". I want to rotate the reference ...
-1
votes
2answers
170 views
Simple Vector Problem [closed]
I'm a bit stuck on a homework question that I've been assigned. The question is as follows:
You are paddling a canoe at a speed of 4 km/h directly across a river that flows at 3 km/h. (a) What is ...
1
vote
1answer
61 views
How to express answers where inequalities are involved?
Part of the floor of a workshop is inclined at 10 degrees to the horizontal. This is to allow the safe storage of steel cylinders. A cylinder of mass 7000 kg is stored as shown in the diagram (c the ...
0
votes
1answer
185 views
Solving inclined plane using diff. frame
I was trying to solve frictionless inclined plane problem using a diff. frame as shown in the figure, and can't figure out that acceleration along the plane = g.sin(Θ), but I think it should be = ...
0
votes
1answer
212 views
A Lawnmower Problem
For my physics class we were just given an exam that asked the following:
A 12Kg lawnmower is pushed with a constant force along the 30* handle with 80N.
Break the Forces into its vector ...
0
votes
1answer
77 views
Finding The Obtuse Angle [closed]
I am working on a simple force problem involving inclines. I found a reference of $48^\circ$, in the third quadrant; now, to find the obtuse angle, do I subtract that value from $270^\circ$, or do I ...
-1
votes
1answer
178 views
How to properly find equilibrium vectors when 3 or 4 vectors are present? [closed]
I'm having trouble regarding how to find the equilibrium of vectors. We were given tables with given information and had to fill them in; I'm fairly sure my initial attempts were incorrect.
first ...
1
vote
1answer
216 views
Is it possible to prove that the curl of a gradient equals zero in this way?
If $(\nabla\times\nabla\Phi)_i = \epsilon_{ijk}\partial_j\partial_k\Phi$, where Einstein summation is being used to find the $i$th component...
Using Clairaut's theorem $\partial_{i}\partial_{j}\Phi ...
0
votes
0answers
314 views
Calculate A and B (Vector) [closed]
The diagram below shows two vectors, A and B, and their angles relative to the coordinate axes as indicated.
http://capa-new.colorado.edu/msuphysicslib/Graphics/Gtype07/prob01a_vectors2.gif
DATA: ...
0
votes
1answer
196 views
Vector Displacement [closed]
A novice golfer on the green takes three strokes to sink the ball. The successive displacements are 4.10 m to the north, 1.90 m northeast, and 1.00 m at 25.0° west of south. Starting at the same ...
-3
votes
2answers
761 views
How to add two perpendicular 2D vectors [closed]
vector D = 4 cm North
vector J = 4.5 cm West
what is D+J?
In a more general sense, how can two 2D vectors that are perpendicular to each other be added?
0
votes
0answers
68 views
How to find the directional cosines?
l+m+n=0 where l,m,n are the directional cosines of a point P in the x,y,z plane. How do I find the angles the radius vector makes with the axes. I get two equations l+m+n=0 and l^2+m^2+n^2=1. But how ...
1
vote
1answer
114 views
Determine the flow and amplitude equation for thermal energy (with Del operator)
It is a question vector calculus and Maxwell's laws. I put it this way. Let's say, we are working in a $3$-Dimensional space ( e.g $x\cdot y\cdot z = 4\cdot3\cdot2$, a certain room/class of that size ...
0
votes
0answers
66 views
Consider the rectangle ABCD with the following Dimensions abs(BC)=3 and abs(CD)=4, so, abs(AB+BC+CD)=5 [closed]
[Consider, the, rectangle, ABCD, where \left \| \widehat{BC} \right \|=3 , and, \left \| \widehat{CD} \right \|=4, then, \left \| \overrightarrow{AB}+\overrightarrow{BC}+\overrightarrow{CD} \right ...
1
vote
1answer
169 views
How to determine n equidistant vectors from point P in three dimensions
As an assignment for uni I need to figure out an algorithm that explodes a particle of mass $m$, velocity $v$, into $n$ pieces.
For the first part of the assignment, the particle has mass $m$, ...
2
votes
2answers
303 views
2D - Kinematics - Linkage System using Vector Algebra
I have this question that I dont know how to solve correctly :
My question is, how do I find $V_B$ ? I will find the angular velocities myself, but I want to know the method to get $V_B$ ?
I know ...
0
votes
2answers
190 views
Find vector position in time give this graph?
Graph is position x position. There are 3 points, $A$, $B$ and $C$.
$A(0,2)$
$B(4,2)$
$C(6,0)$
Particle travels from $A$ to $B$ and from $B$ to $C$ at constant $v = 2 ~m/s$.
Find vector ...
0
votes
2answers
183 views
So where is mistake in the formula of wave number (magnitude of wave vector)?
I have following form for wave vector $k_2=n_2 \omega/c_0$. Now because $\omega=2 \pi c/ \lambda$, then $k_2=n_2 \omega/c_0=\frac{n_2 2 \pi c_0}{c_0 \lambda}=\frac{n_2 2 \pi}{\lambda}$. But problem is ...
1
vote
2answers
211 views
Kinematics Problem
The question asks me to find the angular velocity.
Now I do not want you to solve my homework, I want explanation please.
It states that the acceleration of point P is $\vec{a}= -3.02 \vec{i} ...
0
votes
2answers
347 views
Question involving Vectors and Forces
This is a question I found in Mechanics for Engineers by Beer & Johnston.
A 600-lb crate is supported by the rope and pulley arrangement as shown below.
Write a computer program which can be ...
-1
votes
1answer
370 views
The acceleration of a particle moving only on a horizontal plane is given by a= 3ti +4tj, [closed]
The acceleration of a particle moving only on a horizontal plane is given by a= 3ti +4tj, where a is in meters per second-squared and t is in seconds.
At t = 0s, the position vector r= (20.0 m)i + ...
0
votes
1answer
227 views
Finding The Resultant Vector [closed]
A plane is flying southeast at 215 km/h. Suddenly there is a wind from the north at 75 km/h. What is the plane's new velocity with respect to the ground in standard position?
0
votes
2answers
1k views
Find the Unit Vector of a Three Dimensional Vector
How can I find the unit vector of a three dimensional vector? For example, I have a problem that I am working on that tells me that I have a vector $\hat{r}$ that is a unit vector, and I am told to ...
0
votes
0answers
70 views
Vector Calculus - Mass of a block (I'm being dense) [closed]
I'm currently revising for some exams, and as part of one of my practice questions am finding the mass of a block by use of it's mass density function. It involves a triple integration as seen below. ...
0
votes
1answer
200 views
Calculating vector of plane resulting from tailwind
In some basic physics homework I have, it asks what the resulting vector would be for a plane traveling at x m/s in y direction that is affected by a tailwind going in z direction at w m/s. How would ...
0
votes
0answers
113 views
Vectors and finding lines on a point [closed]
Long John Silver, a pirate, has buried his treasure on an island with five trees located at the following points: A (30.0m, -20.0m), B(60.0 m, 80.0m), C (-10.0m, -10.0m), D (40.0m, -30.0m), and ...
-1
votes
1answer
1k views
how to calculate the angle in the x-y, y-z, x-z plane given only 3D vector direction and magnitude? [closed]
Please help me solve this. I have been thinking of all sorts of ways to solve this but can't figure out how :(. Ok here's the problem:
I am given a three dimensional velocity vector (i know the ...
0
votes
2answers
392 views
Understanding weight on an inclined plane
I'm trying to solve a problem where I have an object resting on an inclined plane, with the angle of the plan being alpha, and the weight being w. I'm having trouble figuring out how I can calculate ...
0
votes
3answers
1k views
Vector product in 2 dimensions [closed]
If I have a vector A=4i+3j and B=5i-2j, how can I find the vector product AxB? I know that given the angle, its C=AB sin theta, but how can I solve this without the angle?
