All Questions
Tagged with kinematics time
101 questions
26
votes
21
answers
5k
views
What happens when a car starts moving? The last moment the car is at rest versus the first moment the car moves
Imagine a car that's at rest and then it starts moving. Consider these two moments:
The last moment the car is at rest.
The first moment the car moves.
The question is: what happens between these 2 ...
- 371
0
votes
1
answer
39
views
Extrapolating time to infinity for a particle moving spirally outward
If I have a particle moving radially away from me in a straight line and I extrapolate time to infinity, I could see the particle in a particular direction (given enough time for the light to reach me)...
- 1,254
-1
votes
1
answer
110
views
Speed is equal to distance divided by time but is this correct?
In this study https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9784821/, the distance the punch travelled from start to impact is 0.49 meters and the time taken from start of punch (that's it, they define ...
- 364
0
votes
1
answer
47
views
A change in the unit vector over a finite time interval
how we can write the change in unit vectors over a finite time interval, the change in unit vectors in an infinitesimally small-time interval 'dt' is given by the magnitude of the really small angle ...
- 51
0
votes
1
answer
99
views
Given a distance, and velocity as a function of time, how do I find the time taken to travel the distance? [closed]
Given the velocity of a particle as a function of time V(t), and a distance between two points on a straight line (from point A to point B), I would like to find the time it will take the particle to ...
- 605
0
votes
0
answers
25
views
A ball dropped onto a rotating wheel of various frequencies experiment issues
I'm doing a experiment to find the relationship between the frequency of the rotating wheel and the horizontal distance travelled by the ball dropped onto it. I am manipulating the frequency of the ...
1
vote
1
answer
185
views
In a uniformly accelerated motion experiment, the acceleration can be attained from $V_{ave}$ vs. $t/2$ and $x$ vs. $t^2$ graph. How is this possible?
Specifically, in the experiment, we had to release a glider from an inclined plane (that had an angle of inclination of 10 degrees). We had to calculate the time it reaches the final position. We had ...
- 13
-5
votes
1
answer
76
views
Reality of speed and time [closed]
I have a very simple question. How does a faster object takes less time for the same distance? A car with a speed of 100km per hour takes one hour to travel 100km while a car with the speed of 50km ...
0
votes
0
answers
33
views
I need a ship at rest to accelerate under preferably constant acceleration/deceleration to arrive at rest at an object 55 AU away [duplicate]
I'm working on the story and I need help with the plot point. Assume that the energy needed for constant acceleration is not a problem. And there's no need to complicate this with outside forces.
I ...
-2
votes
2
answers
113
views
If an object is travelling at say 35 mps, if I somehow stop the time, is the speed zero or 35 mps? [closed]
I know we only go close to zero, not equal zero, but if that somehow happens, will it be zero as it is at rest or 35mps as when you resume the time, the speed is 35mps?
0
votes
1
answer
89
views
Is average velocity equal to displacement per unit time OR displacement divided by time?
I had looked for the definition of average velocity in books like Resnick Halliday, Tipler ' Sears zemansky but no book writes average velocity as displacement per unit time although in these books ...
- 1,395
0
votes
2
answers
194
views
When will the 2 cars Have equal speeds? [closed]
If car1 started at 20m, with initial velocity of -4m/s and acceleration of 3 m/s^2.
Car 2 started at 15m, with initial velocity of 6m/s and acceleration of 0. At what time will the 2 cars have equal ...
- 103
-2
votes
2
answers
191
views
If time is denoted by an imaginary number, what does that mean? [closed]
Suppose, the initial velocity of a car is 1m/s, acceleration 2m/s^2, distance travelled (-8)m. What is the time required to reach that distance? This is the first question.
The answer of the first ...
- 15
3
votes
1
answer
239
views
Why does it take $2d/\lvert v_1 - v_2\rvert$ time to overtake? (Can physics catch-up to math?)
The following answer is from this post.
So it becomes particularly easy to see that the opposite-direction meetings must occur at the interval $2d/(v_1 + v_2)$ and that the overtaking meetings must ...
- 177
2
votes
0
answers
71
views
Number of meetings of $2$ cars starting from opposite ends of a road [closed]
Question:
$2$ cars travelling at $108,75$ kmph respectively, start from the opposite ends of a $90$ km straight road. Travelling back and forth continuously for $10$ hours, how many times do the $2$ ...
- 177
1
vote
3
answers
95
views
What is the rate of change of time wrt velocity of an object?
disclaimer, I'm just an average highschooler so please be a little friendly with the mathematics of your answers but I wondered what would be $dt/dv$?
- 33
0
votes
1
answer
80
views
Why do my equations say that an object thrown at $30^o$ with velocity 30 m/s has a $y$ velocity of 15 m/s? [closed]
I don't know if I have stumbled upon a genuine truth, or if I'm doing something very wrong. But here is my problem:
I am modelling the 2D trajectory of an object with constant acceleration using ...
- 329
0
votes
4
answers
186
views
Is this $x$-$t$ graph possible? Is the distance decreasing over time in this graph?
I have read in a Book:
But I think it is possible as a Negative Velocity and Positive Acceleration:
Reference:
SL Arora Physics Class 11, Pg No. 152.
6
votes
4
answers
778
views
Finite distance, Infinite time?
Let's say that a ball dropped from $1 \ \text{m}$, covers $\frac{1}{n^2} \ \text{m}$ for every $n$ bounce, i.e $\sum_{n = 1}^{\infty} \frac {1}{n^2}$ so the total distance will be $\frac{π^2}{6}$, ...
0
votes
2
answers
47
views
How to find time taken for a faster object to cross a slower object of same length, both moving parallel to each other in the same direction? [closed]
Can you explain me how to determine the time taken for a faster object to cross a slower object when they're both of same length and are moving parallel to each other in the same direction?
- 3
1
vote
4
answers
853
views
Why are areas of graph taken with respect to $t$-axis in velocity time graphs?
If the following graph is given then, why is the displacement equal to the area of the shaded triangle above the axis minus the are of the shaded triangle below the $t$ axis.
Why can it not be area of ...
- 49
0
votes
3
answers
67
views
Different equation is given for "position"
$$s=ut+\frac{1}{2}at^2$$
Assuming, $u=0$
$$s=\frac{1}{2}at^2$$
$$a=\frac{2s}{t^2}$$
So I got a function for acceleration.
$$v=u+at$$
$$v=\frac{2s}{t} \tag{1}$$
In reality I know that $s=vt$ when ...
- 91
0
votes
1
answer
31
views
How much time does it take bodies to change their current state of motion?
Correct me if I’m wrong in any of this
bodies with mass tend to resist any change in their state of motion .. if they are at rest .. they resist motion and if they are in motion they resist being put ...
- 3
0
votes
1
answer
54
views
What would be the right equation to use?
I am working on and needed assistance with the Moving Man Simulation. If I wanted to illustrate The Man at an initial starting point/position of $+1$, with a Velocity of $-2$, what equation could I ...
- 111
1
vote
2
answers
227
views
Force from time and velocity
Let's say I have a goal velocity $(v)$. In $n$ amount of time $(t)$ (let's say two seconds). What is the formula for finding the amount of force I would need (not counting other forces like drag/...
- 75
0
votes
1
answer
358
views
How to find time at any point on the path of a projectile motion?
I know how to find the time of flight and all but what if I chose a random point on the path of the projectile (no air resistance) and ask the time at which the particle is present there, then how can ...
-1
votes
3
answers
352
views
What does this displacement time graph say about velocity?
I have a debate with my sister, who says that velocity should be constant because velocity is $\dfrac{d}{t}$ and there certainly is some non-zero displacement. I say velocity is the rate of change of ...
- 1,200
1
vote
2
answers
2k
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What is distance multiplied by time?
From grade 6th we have been taught that if we find the area of the velocity-time graph is distance covered or in other words if velocity is constant then distance= velocity* time as velocity = ...
- 21
1
vote
3
answers
2k
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One ball is dropped at a height, and another ball is thrown up with the final velocity of the first ball. Where do they meet? [closed]
I've found variations to this problem on stack exchange, but in most of them the initial velocity is varied.
In this version, you first drop the ball at the top of the building, and measure its final ...
- 131
3
votes
3
answers
6k
views
Meaning of negative time
Whenever we graph time along a $x$-axis, we graph it along negative and positive $x$-axis both. So what does a negative time mean in the negative case axis? What does the negative sign indicate?
- 65
11
votes
9
answers
1k
views
Is velocity real?
This sounds like a stupid question but I am do not grasp physics concepts easily. "Velocity" is just the change in displacement over the change in time. I can see displacement and time as ...
- 127
1
vote
1
answer
57
views
How to calculate the components of the displacement of unit magnitude of an accelerating particle in 2D? [closed]
A particle is moving in 2D having a constant acceleration $ \vec a $.
Given initial velocity $ \vec u $, after time $ t $ the magnitude of its displacement $ \vec S $ is 1.
I need to calculate $ S_x $...
- 227
0
votes
4
answers
497
views
Can we explain velocity without time? [closed]
I'm trying to wrap my head around inertia/velocity, or just change in general, I guess. I'm unsure exactly sure were my gap is, or what question to ask, so I'll explain with a scenario.
Lets say I'm ...
- 117
1
vote
2
answers
90
views
Can there exist a motion which cannot be described as a function of time?
I know there exist systems for which we cannot solve its differential equation, But I was wondering if there could be a motion that cannot be represented as a differential equation with respect to ...
- 17
0
votes
1
answer
21
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One-dimensional harmonic move - input parameter conversion
I have one-dimensional harmonic move, but velocity is defined as function of distance from the beginning
V(x) = (Vmax + Vmin)/2 + (Vmax - Vmin)/2 * cos((2 * PI / K ) * x )
Where Vmax > Vmin, Vmin &...
0
votes
2
answers
246
views
Why are these SUVAT equations true?
\begin{align}
v&=u+at\\
s&=ut+\frac{1}{2}at^2\\
v^2&=u^2+2as\\
s&=\frac{(v+u)t}{2}
\end{align}
I have just started with learning acceleration in school and I don't really understand ...
- 119
0
votes
1
answer
352
views
Acceleration function of position and time
I have an acceleration function in python with position and time parameters and returns the acceleration value.
I need the end velocity at a position ,start velocity is zero.
how to calculate this ...
-1
votes
1
answer
78
views
Hello, can anyone please help me understand and solve the problem? [closed]
ABCD is a track with a horizontal section BC of length 5 m. A 0.3 kg steel sphere is released from a point on the slope AB and it rolls towards the end D of the track. A stop watch was started shortly ...
- 11
2
votes
5
answers
276
views
Why should the particles meet at a common point? [closed]
I saw a question in my physics book asking for the time when all the three particles (each at the corner of an equilateral triangle and each having constant velocity v along the sides of the triangle) ...
- 8,476
0
votes
1
answer
3k
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How to determine the correct time using quadratic functions if there are multiple "correct" roots exist in a 3D system? [closed]
Time can be calculated from a modified kinematics quadratic formula using the initial velocity, displacement, and acceleration. However, the acceleration vector isn't limited to 1 axis.
When applying ...
- 101
1
vote
0
answers
42
views
Problem 1: Sophism MIR publication [closed]
I am trying to solve the very first problem from the book "Physical Paradoxes and Sophism"
The problem is as under:
1.1. The Amazing Adventure of a Subway Passenger:
Every morning a ...
- 823
3
votes
1
answer
59
views
If a device's uncertainty for measuring time is $ 10^{-4} $, what happens to the uncertainty when the experimental value is squared?
In a case where the device's uncertainty is found to be $ 10^{-4} $. As it is a device that measures a time interval; when squaring the experimentally obtained value, what should one do with the ...
- 177
1
vote
11
answers
2k
views
Are time and motion the same thing?
My question might be completely irrelevant or stupid - sorry in advance if it's the case. I'm kinda lost with the time and space notions, and even formulating adequate questions is hard at that point.
...
- 597
1
vote
5
answers
2k
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Calculating mean velocity: using time or velocity? [closed]
Background
I have been running tests which involve timing an object moving a certain (fixed) distance, $s$.
Each test has been repeated 3 times, and the 3 times ($t{_{1}}, t{_{2}}, t{_{3}}$) for the ...
- 113
7
votes
7
answers
13k
views
What is the difference between position, displacement, and distance traveled?
Suppose the question is somewhat like this:
If $v=8-4t$ and the position at time $t= 0\ \rm s$ is $2\ \rm m$, find the distance traveled, displacement, and final position at $t=3\...
- 75
-5
votes
3
answers
550
views
WHY did physicist defined velocity as displacement divided by time, why not displacement * time? [closed]
V=S/T. As per my knowledge i think ratio as division and it don't give any meaning like this much displacement in this much time. So i think physicists only used division as notion for velocity. But ...
- 29
1
vote
1
answer
81
views
Doubt in this displacement-time graph [closed]
According to a book, this is a graph of "a ball resting on a smooth floor is kicked which rebounds from a wall with reduced speed. It then moves to the opposite wall, which stops it."
My Question ...
- 179
0
votes
7
answers
4k
views
What happens to velocity when Time equals zero?
I am not formally educated in Science but natural questions have always intrigued me.The way I put it is that I am married to Commerce but Science has been a childhood love. Now I have this very basic ...
4
votes
3
answers
154
views
What is the best way to conceptualise a 'division' [closed]
This may seem like a strange question, but my question is more along the lines of trying to figure out how people were able to 'discover' the formulas which have shaped our understanding of the ...
- 143
0
votes
2
answers
3k
views
What would the position vs. time graph look like if the velocity vs. time graph was a curve?
In my physics class we are learning about velocity vs. time graphs and position vs. time graphs for an object. We have learned that if the object is moving with constant velocity (this would be a ...
- 129