All Questions
21
questions
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Wording of Relative Velocity problems [closed]
I've been doing some relative velocity problems. The three main types I do are to do with cars, boats/rivers and planes/crosswind.
I'm fine with cars as the wording is pretty straightforward - it is ...
- 27
1
vote
2
answers
7k
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What will be the minimum drift possible when a boat crosses a river? [closed]
Imagine a boat with a constant speed $v$ that has to cross a river of width $d$. Let the river flow with a constant velocity $u$. I want to know the angle at which the boat should sail in order to ...
0
votes
0
answers
3k
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On a rainy day, a man is running on a hilly terrain in such a way that he is always finding the rain drops hitting him vertically
It is assumed that rainfall is uniform in the whole terrain from O to E(figure attached) When the man was at rest on stretch OA, he found the rainfall at an angle of $30^o $ with the vertical.
What ...
- 309
-1
votes
1
answer
52
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Why is direction of train like this for car?
This is an image of a train and a car. T is the train moving towards - $x$ axis and C is the car moving towards $+ y$axis.
So, my teacher made a resultant velocity with $-5\hat i$ and $-20\hat j$. ...
- 725
0
votes
1
answer
38
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Direction of $V_RM$ confusion
So ,please read both the questions . They have similar originate questions that I am facing difficult in.
Let us say rain is falling downwards with v = -5j and a man is moving with a velocity of 2i in ...
- 725
-1
votes
2
answers
91
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Velocity Question from grandparent
My Grandparent asked me this question a few years ago, and I am getting around to giving him an answer, but I don't know the answer. Can anyone help?
"A pickup truck is speeding along a highway ...
- 21
-2
votes
1
answer
69
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Problem regarding relative velocity [closed]
Train A moves north with speed 54km/h. What is the velocity of a monkey running on roof of a train A against its motion (with velocity of 18km/h with respect to A)as observed by a man standing on ...
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-1
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2
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4k
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What does speed of an object relative to water mean?
A swimmer swims with the velocity 1.25 m/s "relative to water". He has to swim across the river which is 150 meters wide. If his direction of velocity is perpendicular to the stream, he is taken away ...
- 203
0
votes
1
answer
605
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Is this Question correct? Newtonian Motion - Relative Motion of Rain
There is a question in a textbook which states:
"A cyclist is riding north at 12km/h when it starts to rain. The rain appears to be falling towards her at an angle of 10 degrees relative to the ...
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-2
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3
answers
1k
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Swimming across a river [closed]
I have come across a physics riddle where 2 swimmers with same speed $c$ are competing against each other in a river, they start at the same spot, first swimmer (s1) is swimming distance $d$ up stream ...
- 107
0
votes
2
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1k
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Relative velocity in two dimensional motion [closed]
I came across the following problem in my textbook:
"Two particles A and B are projected in air. A is thrown with a speed of 30m/s and B with a speed of 40m/s as shown in the figure. What is the ...
user106570
1
vote
2
answers
342
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Velocity of approach of a beam of light and a moving object
I came across a problem on Brian Greene's course on Special Relativity.
(http://www.worldscienceu.com/courses/6/elements/TnRUSU)
From George's perspective, how fast does a beam of light approach ...
- 777
1
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1
answer
3k
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Finding resultant and direction of resultant
In this question-
A motorboat is racing towards the north at 25km/h and the water current in that region is 10km/hr in the direction of 60 degrees east of the south. Find the resultant velocity of ...
- 715
0
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1
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152
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Is there any significance to the negative sign on this speed?
A girl is riding a bicycle along a straight road at constant speed, and passes a friend standing at a bus stop (event #$1$). At a time of $60$ s later the friend catches a bus (event #$2$)
If the ...
- 165
0
votes
1
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2k
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Finding an equation to solve for the velocity of a swimmer crossing a river [closed]
Where $\theta=45^\circ$, $d_1=200\:\mathrm{m}$, and $d_2=150\:\mathrm{m}$.
I do not know how to combine the following equations:
$$\begin{align}
t&=\frac{d_1}{v_s\cos(45^\circ)}\\
t&=\frac{d_2}...
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