Linked Questions

16 votes
3 answers
3k views

How does anything move? [duplicate]

So in order for two things $A$ and $B$ to move apart, for example, relative to each other, $B$ can be set into motion away from $A$. This means that we have to increase $B$'s velocity and therefore ...
under_the_sea_salad's user avatar
-2 votes
2 answers
154 views

Apparent paradox of motion [duplicate]

I have what appears to be a paradox of motion, but it could just be my misunderstanding. It works under the assumptions that motion is fundamentally continuous, that position, velocity, acceleration ...
Ryan Cole's user avatar
1 vote
2 answers
85 views

For regular moving objects around us, how many times can I differentiate their position with respect to time until I reach a constant? [duplicate]

When I practise problems, I come across ideal situations like constant velocities, constant accelerations, etc. But in real situations, objects usually don't magically gain momentum or acquire ...
Reet Jaiswal's user avatar
0 votes
1 answer
177 views

Acceleration as the second derivative of $e^{-\frac{1}{t^2}}$ [duplicate]

If we have, say, a material point with a zero velocity at the time $t=0$, and this point starts moving at a time $t>0$ , then we look at the force impressed on the point by inspecting the second ...
HaroldF's user avatar
  • 139
3 votes
1 answer
132 views

Can a "flat function" be a particle trajectory? [duplicate]

Recently I came across the concept of a flat function, which is a smooth function $f:\mathbb{R}\to\mathbb{R}$ all of whose derivatives vanish at a given point $x_0\in\mathbb{R}$, the canonical example ...
Harald's user avatar
  • 761
1 vote
0 answers
93 views

Does car move when instantaneous velocity is zero? [duplicate]

In 3blue1brown: derivative paradox. supposed car moving with: $S(t) = t^3$ And velocity is: $V(t) = 3t^2$ He asked when t = 0 velocity is 0 m/s , does that car move at that time ? And here his ...
Heroz's user avatar
  • 311
50 votes
5 answers
10k views

Norton's dome and its equation

Norton's dome is the curve $$h(r) = \frac{2}{3g} r ^{3/2}.$$ Where $h$ is the height and $r$ is radial arc distance along the dome. The top of the dome is at $h = 0$. Via Norton's web. If we put a ...
countunique's user avatar
  • 1,751
29 votes
1 answer
5k views

What situations in classical physics are non-deterministic?

In Sean Carroll's book "The Big Picture," he states (chapter 4, page 35): Classical mechanics, the system of equations studied by Newton and Laplace, isn't perfectly deterministic. There are ...
WillG's user avatar
  • 3,566
4 votes
2 answers
616 views

Non-uniqueness of solutions in Newtonian mechanics

In The Variational Principles of Mechanics by Lanczos, in section 1 of Chapter 1, Lanczos states that for a complicated situation, the Newtonian approach fails to give a unique answer to the problem, ...
user31350's user avatar
1 vote
3 answers
252 views

Why does a particle initially at rest at origin with acceleration as square of its $x$ coordinate ever move?

Consider a particle initially at rest at origin, with acceleration, $a$, such that $ a(x)=x^2$. Since the particle is at origin, initial acceleration would be 0. It's also at rest initially. Its $x$-...
brainfreeze's user avatar
0 votes
2 answers
490 views

Acceleration with zero initial power?

Power = Force x velocity At the initial instant, the velocity = 0, so the power is zero, even though there may be force, but zero power is taken from that force. So how can the object even start ...
user1648764's user avatar
  • 1,956
0 votes
2 answers
113 views

Is the motion of a particle non-analytic?

I really can't understand what happens during the time $t(0)$ to $t(0+dt)$ in the following crackpot arguement: A particle is at rest (in an ideal frictionless world) until $t(0)$. So every order ...
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