Newtonian mechanics covers the discussion of the movement of classical bodies under the influence of forces by making use of Newton’s three laws. For more general discussion of energy, momentum conservation etc., use classical-mechanics, for Newton’s description of gravity, use newtonian-gravity.

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Using Conservation of momentum and Energy to solve a problem [closed]

A 9kg bullet is fired horizontally into a 10 kg block of wood suspended by a rope from the ceiling. The block swings in an arc, rising 6mm above its lowest position. Find the velocity of the bullet. ...
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2answers
63 views

Speed needed to make a car jump from a ramp

(I've posted this question on GameDev and I've been told to ask here so I'm pasting the question) I need to make a car jump from a ramp to another, and I need this to be done using AI so I thought it ...
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2answers
65 views

Is potential energy an energy exists or potentiality of energy? [closed]

I want to ask whether Potential Energy is truly existing Energy - though i know the energy concept is abstract and we do not know what is energy truly as Feynman said - or it is the potentiality that ...
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0answers
27 views

What is the effect of vibrations on an object's properties?

What do vibrations do to an object's properties? By making an object vibrate at a high frequency (compared to its static state) would vibrations: Increase or reduce its moment of inertia? Increase ...
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4answers
78 views

Sun and planets orbit each other

Do not the planets and the Sun revolve in orbits around each other and the shape of the orbit depends on where the center of gravity of the system is? The greater the mass of the Sun, the closer the ...
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1answer
54 views

Spring compressed between two blocks [closed]

I´m trying to solve this problem and I don't understand it well. We have a block whose mass is $m_2$, a block whose mass is $ m_1$, and a spring of length $8a$. If you connect the blocks like this: ...
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2answers
69 views

Clarify an assertion on torques from the Feynman lectures

In The Feynman Lectures, vol.I, chapter 18, Feynman discusses torques on a rigid body in two dimensions and says: Now we pause briefly to note that our foregoing introduction of torque, through ...
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5answers
217 views

How can static friction do work?

By definition, the work done by a force is $W = F\cdot d$, so how can static friction do work? Can this force move the body a distance of $75~\text{m}$?
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1answer
34 views

Frequency response of a capstan-like mechanical amplifier

Tension on a wire can be amplified by wrapping the wire around a powered rotating capstan, with output force governed by the linear capstan equation, Tout = Tin * emu*theta. Will this equation hold ...
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1answer
66 views

Confusion about average force applied over a time interval

If I understand correctly, the word average implies the average of forces acting during a certain time. $$F_{avg}=\frac{\int_{t_i}^{t_f}{F(t)\,dt}}{t_f-t_i}$$ The teacher gave us tasks with answers ...
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0answers
21 views

Constant 2 in kinetic energy equation [duplicate]

Trying to understand where the constant 2 comes from in the kinetic energy equation, $mv^2/2$. Why 2 and not another number?
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1answer
112 views

Exam review problem. Weird answer [closed]

The question asks us to calculate the holding force of the triangular mounting if the rock weighs exactly $2kg$ and the mounting supports the rod at exactly $\frac{1}{4}$ of its length. ($g=9.81 ...
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1answer
43 views

Two Bodies Orbiting Around Each Other and Kepler’s Laws?

If two bodies are orbiting around a central center of gravity, how does Kepler’s first law (the one regarding the ellipse) apply?
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2answers
87 views

Comparing the orbit radius of two spherical objects [duplicate]

Assume the mass of star 2 is 4 times the mass of star 1. Compare the radius of the orbit of star 1 to that of star 2. Possible answers: R1:R2=1:4 R1:R2=1:2 R1:R2=2:1 R1:R2=4:1 R1:R2=16:1 ...
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0answers
46 views

Higher order principle of isotropy

Let us work with classical mechanics in the substantivalist metaphysics, that is, space and time are seen as absolute. Call $n$-th order of motion any observer such that $n$ is the biggest order of ...
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1answer
30 views

Variation in spring constant with respect to the length and no. of coils

Do the spring constant depend upon the length of the spring? No. of coils? Like what happens to the spring constant if you cut it in the half?
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3answers
64 views

Why is there a contradiction in this Newton's equations of motion related question? [closed]

One second after being thrown straight down, an object is falling with a speed of 20 m/s. How much distance does the object travel in the first second? We took: $$v = 20\,{\rm m/s}$$ $$u = 0\,{\rm ...
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1answer
69 views

Work done by friction on car

David Morin, in "Introduction to Classical Mechanics" says that friction does not exert a force on a car because the ground is fixed but that KE of the car is changing to internal kinetic energy in ...
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0answers
28 views

How fast does the force of pulling a straight rope propagate along the rope? [duplicate]

Is it instantaneous or does it somehow propagate like a wave along the particles of the rope ?
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1answer
58 views

Does it take more effort to move against earth's rotation?

I know that if we stand still, we are traveling at 0 m/s relative to the Earth. But if we move against the rotation of the Earth we lower our speed, so, wouldn't we have to fight against the ...
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1answer
52 views

Difference between kilogram-force and kilogram

I know that a 1 kilogram-force is the force of 1 kilogram acted upon by 1 standard unit of gravity (9.80665 m/s^2). However, in torque descriptions I find that some use $kgf*cm$ while others use ...
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1answer
39 views

What does $\bar{x}_{\textrm{el}}$ represent?

In the context of centroids and moments, what do $\bar{x}_{\textrm{el}}$ and $\bar{y}_{\textrm{el}}$ represent? For example: $$\bar{x}L = \int \bar{x}_{\textrm{el}}dL$$ Some references that use ...
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1answer
89 views

Largest size of a low gravity, Earth-like planet with Volcanoes and Earthquakes?

Provided that the Solar System consists only of Sol, a planet, and the planet's moon.... How large can my planet be so that it has low enough gravity that teenage human girls trained for jumping, are ...
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1answer
50 views

Coriolis force: why is pole-to-equator air flow eastly?

I have little knowledge in fluid dynamics, so this may be naive. But I have a question while reading a textbook about the Coriolis force, by which the rotation of the earth from west to east changes ...
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0answers
13 views

Real data on pulleys

Does anyone know where I can find a reference detailing a study of the dynamics of real pulleys? Something including effects of friction, wobbling of the pulley, effects of different types of anchors ...
26
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12answers
3k views

How can the contact point of rolling body have zero velocity?

They say that for a rolling body, the velocity of the contact point is zero. I'm not getting this. How can it be zero when it's in continuous motion?
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0answers
40 views

Orbital elevators and the Coriolis effect

Consider an orbital elevator simply modelled as a large mass in geostationary orbit (altitude approx 36,000km) around the Earth, connected to a point on the equator via a strong, light, likely ...
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1answer
44 views

mechanics problem: rope on a fictionless table through a hole

The problem is from "An introduction to Mechanics" by Daniel Kleppner and Robert Kolenkow. The book has a second edition, and the problem is not changed. The number of the problem is 4.16 in second ...
2
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5answers
300 views

when an object is lifted (at a constant velocity) shouldn't the work done on the object be zero? [duplicate]

When I lift an object from the ground (at a constant velocity) I'm applying force on the object equal to its weight and the earth is also pulling it downwards with equal amounts of force. So if the ...
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1answer
26 views

Can the gravitational constant be directly measured?

The value of the gravitational constant $G$ is $6.67384\times 10^-11 {\rm m}^3{\rm kg}^{-1}{\rm s}^{-2}$. This value is used in the formula to calculate the attractive force between two objects with ...
2
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4answers
118 views

If velocity is constant, how can $p = F\cdot v$ be non zero?

If an airplane of mass $m$ is flying at a constant speed $v$, the power of the airplane is $$P = m\cdot v\cdot g $$ where $g$ is the acceleration of gravity and therefore: $$ F = m\cdot g, $$ but, ...
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1answer
40 views

Confusion regarding area from graph

This might be a trivial question but is illustrated below. Why is the area 'below' the graph always taken for a velocity-time graph when finding the displacement? I mean why is the area with the time ...
3
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1answer
76 views

Physics simulator based on conservation laws?

Reading the article: http://en.wikipedia.org/wiki/Newton%27s_laws_of_motion#Relationship_to_the_conservation_laws there's a section stating that: ...
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1answer
163 views

Finding the distance without using time as a variable

A small child with mass $M$ rides down an icy slope of height $h$ and inclination $\theta$ on a toboggan of mass $m$. At the bottom of the slope they continue to slide on flat ground, slowing and ...
1
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1answer
39 views

Problem about a spring which oscillates due to a external force [closed]

A person holds a spring of stiffness $k= 80$ N/m by its extremity A; In the other end there is a mass of $0.5$ kg. The spring is initially at equilibrium, when the person starts to shake the ...
3
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2answers
68 views

How can I find the angular and linear velocity of a 2D body that breaks into two bodies?

Afternoon. This is my first question, so do let me know if I'm doing anything wrong. Looking for help on building a 2D physics game engine with bodies that split in half: I have a two dimensional ...
0
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2answers
34 views

Find max height [closed]

I have stucked with finding max height of an $m$, given only $m, M$ and initial velocity of $m$ - $\vec{V}$. There is no friction in the system. As I understood I need to find $\vec{V_0}$ - velocity ...
13
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4answers
519 views

How can I relate linear and angular motion using a single formula?

I want to relate linear and angular motion using a single formula. Assume I have a 10m rod, and I apply a force of 5N on it, 2.5m away from the axis of rotation for 1s. How can I determine the ...
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0answers
12 views

Pressure change in throttling & flow rate reduction in a water circulation

If the pressure in a water pipe line is reduced from 7kgf/cm2 to 4 kgf/cm2, what is the % reduction in flow rate?
0
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1answer
56 views

Oscillation of a vertical rod supported by horizontal spring [closed]

The system seems to oscillate with $\omega = \sqrt{\frac{\frac{3}{2}mgl + 3k a^2}{ml^2}}$ for small angle $\theta$, and in particular for whatever stiffness $k$ chosen relative to gravitational ...
3
votes
1answer
52 views

Calculating Angular Acceleration of a Rolling Object

A bowling ball of mass M = 6.50 kg, radius R = 10.0 cm, and moment of inertia I = $(2/5)MR^2$ is given an initial center of mass velocity $v_0 = 3.00 m/s$ that is parallel to a horizontal surface. ...
4
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3answers
200 views

Can we rigorously define force?

I'm looking to get rigorous definitions on which to base the important quantities in classical mechanics. To me a "rigorous" physical definition is an operational definition -- that is one in which ...
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2answers
56 views

Need derivation of a formula related to determination of moments of a object about $x$-axis and $y$-axis

I'm given a plate,its density $\rho$ and it is the region bounded by the two curves and on the interval [a,b].I want to find the center of mass of the region below. I’ll first need the mass of ...
2
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0answers
58 views

What is the physics in a balero toy?

A balero is a wooden ball tied with a string to a rod. The string ties to the ball at one end (say North pole), and there is a hole drilled in the ball at the other end (South pole). The hole is the ...
0
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1answer
44 views

Determining the force of a spring

How can I determine the maximum force a spring can release when it pops up? Is there even a formula for this?
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1answer
37 views

Resolution of force vectors

For example in a simple pendulum problem.. the forces that act on the bob are tension and gravitational force. but while the resolving the vectors to find T(tension) at any given angle x with the ...
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1answer
22 views

Stair well descent

I am trying to understand the science behind lowering a person down a flight of stairs on a sled. My tensile strength only says it can hold 250 pounds but I have seen it lower people that weigh 300 ...
3
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4answers
429 views

Is this solveable? Simultaneous elastic collision of 4 objects in XY plane

I'm writing a computer program/game and can't figure something out; I want to be able to calculate the resulting velocities of 4 particles (hexagons, specifically) after they simultaneously ...
0
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1answer
86 views

Would a planet in a binary star system follow Kepler's Laws?

I'm thinking it would not. I am thinking Kepler's Laws were a simplification that were possible with a simple two body (sun, planet) but would not apply for something more complex (sun1, sun2, ...
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2answers
75 views

Rocket Altitude Calculation

Assignment Basic data I was launching a rocket model and I tried to calculate the reached altitude. The engine (C6-0) impulse is 10 Ns Total weight is 65,7 g (includes the engine) I calculated ...