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.

learn more… | top users | synonyms (2)

0
votes
3answers
48 views

Orbital motion with varying radius

The model of a orbital motion in many Physics textbooks and online resources (e.g., Wikipedia on circular motion) assumes that the orbit is a circle, i.e. the radius is constant and the speed is ...
1
vote
1answer
85 views

Different solutions for floating a DIY torii gate deeper than it's original floating level [closed]

I'm facing a dead end with my physics experience on a new build I am working on. Any help would be appreciated. Basic problem: I am trying to build a floating wooden Torii gate to be placed on water ...
1
vote
3answers
57 views

Electrostatic and gravitational forces? [closed]

Electrostatic force between two charged particles depends on the magnitude of the charges and the distance between them. If the charges have mass $m$ and $m'$ then, what will be the total force ...
2
votes
3answers
91 views

Why do objects fall at the same acceleration?

I read these two posts and now I am more confused. Do heavier objects fall faster? Don't heavier objects actually fall faster because they exert their own gravity? I was going to ask: if mass ...
0
votes
1answer
46 views

velocity in inertial and nontial frames

I got confused about the difference between the last term of both pictures. In the first one, we have w x r, but in the second we have w x r underlined. Does anyone have a better explanation? They ...
3
votes
2answers
41 views

Internal potential energy and relative distance of the particle

Today, I read a line in Goldstein Classical mechanics and got confused about one line. To satisfy the strong law of action and reaction, $V_{ij}$ can be a function only of the distance between ...
0
votes
2answers
51 views

How to deal with non fixed springs? [closed]

In every physics book they explain how to compute the force that a spring exert if one of its ends is fixed to a wall (or equivalent) and the other end is compressed or stretched. But how to deal ...
0
votes
1answer
85 views

Gravitation - why is it so confusing?

First, does gravity emit from all directions around a star or planet equally. Secondly, how is it that gravity pulls a planet closer, then it goes further out, without the planet changing orbit ...
1
vote
1answer
56 views

What are Lagrange points in gravitation fields? [closed]

What are Lagrange points in gravitation fields? Additionally, what are their properties? For example, if a satellite or asteroid rested at a Lagrange-point.
0
votes
1answer
37 views

Simple question about circular motion

The picture below shows a page of my mechanics (M2) textbook. At the top of this page, you'll see that it says that "a=-ω^2r". Why is it then that all the answers to the question in exercise 6B ...
0
votes
2answers
87 views

Derivation of Lagrangian?

I know that the Lagrangian $L$ is defined to be $T-V$, i.e. the difference between kinetic energy and potential energy. Also the Action $S$ is defined to be $\int Ldx$ and from this we can derive ...
4
votes
4answers
113 views

Does car have more kinetic energy when turning?

I asked this Phys.SE question Does car lose kinetic energy when turning? Assume a car turning without losing its speed by holding to a point by a rope. IMO, while the car is turning, its kinetic ...
0
votes
1answer
40 views

Loss of kinetic energy in inelastic collision [duplicate]

I know that momentum and energy are always conserved in collisions, but if we have a perfectly inelastic collision in which an object sticks to another object $m_1 v_1 + m_2 v_2 = (m_1+m_2)v_{12}$, ...
0
votes
1answer
44 views

Recoil from a shotgun

First of all I'd like to point out that I'm a complete layman when it comes to physics and I apologise if this isn't the correct forum for this. If I were to sit on an office chair on a laminated ...
0
votes
3answers
159 views

Pendulum (highschool)

I have a question concerning pendulum. On our physics lessons we built simple pendulum consisting of weight and a thread ($\ell=0.31$ m). We tried to calculate $g$ from the well known formula $$T_m ...
2
votes
1answer
77 views

How is circular motion possible on a banked road when there is no Friction?

It is given here that the maximum safe speed of a vehicle on a banked road having coefficient of friction $0$, is $V =\sqrt{R g \tan \theta}$, where $\theta$ is the angle of banking. I can't ...
0
votes
1answer
24 views

Minimize initial velocity of projectile to arbitrary point

I'm supposed to shoot a projectile from the origin to a point $(x_0 , y_0)$ with minimal initial velocity $v_0$. (no air resistance; regular gravity) The flight time should be $T=\frac{x_0}{v_x}$. ...
1
vote
2answers
38 views

Centrifugal force when there is no friction [duplicate]

Assume that a coin is placed on circular disk and now a disk is rotated with constant angular velocity. If there is no friction between the surfaces of a disk and coin, according to theory the coin ...
0
votes
0answers
30 views

Propeller Force & Momentum

An air stream is created by a propeller at velocity $\nu = 93.6\frac{m}{s}$ To calculate force applied by the propeller I used this formula: $$F=\frac{1}{2}\rho\nu^2A$$ where: $\rho = 1.29 ...
1
vote
1answer
65 views

Calculating the time to stop a wheel with friction [closed]

I'm trying to solve the following problem, but i have no idea how to begin. A wheel of mass $M$, radius of gyration $k$, spins smoothly on a fixed horizontal axle of radius a which passes through ...
1
vote
3answers
242 views

How long does it take for an electric car to go from 0 to 60 mph?

I found the freefall motion equation which describes terminal velocity of a falling body, but I can't find a similar equation for a vehicle subject to constant traction force, so I tried determining ...
0
votes
3answers
62 views

Newton's third law of motion

Action has equal but opposite reaction then, why dont a ball keep on moving when made to move between two surfaces,should elasticity of surface,gravity and friction be mentioned in this theory?
0
votes
1answer
22 views

Work done in non-uniform circular motion

In non-uniform circular motion, the work done by force should not be zero because tangential force acts on body. Is this correct? If I am wrong, please give a proper explanation.
3
votes
0answers
47 views

What is the maximum range of a bullet flying through the sky? [closed]

How far would my bullet fly with the following characteristics? 1.2km/second initial velocity 45 degree angle into the sky 'Normal' atmospheric conditions No wind Typical high-powered rifles have ...
1
vote
0answers
21 views

What is the speed of a thrown ball [closed]

I would like to know how much speed is loss when a baseball is pitched. When a pitcher hurls the ball, it must lose speed before the catcher catches it because of the air resistance. So, if the ...
0
votes
0answers
24 views

Best books for high-school? [duplicate]

Please don't close this thread, I now it might sound like a dozen others but I think that every case is different... I go to the first class of high school (that's how it's called in Greece, not sure ...
7
votes
1answer
466 views

Camp Fire Crackle

I was sitting around the camp fire and there was a periodic sound of cracking and pieces of the burning wood flew off. My question is what is the mechanism for the cracking of the wood? I was thinking ...
4
votes
1answer
64 views

Faster than critical damping for harmonic oscillator?

The image below shows damping for spring oscillator with Hooke law F=-kx and damped with F=-cv where: k is spring constant x is oscillator position c is damping coefficient v is velocity of oscillator ...
1
vote
0answers
34 views

How does a simple weighing balance actually work? [duplicate]

I have made a simple sketch of how I think the system looks like. My problem is: I always thought that the angle the balance makes is a function of the difference between the two masses (or the ...
0
votes
1answer
18 views

Do I need the exact velocity when experimenting with sliding coins?

I'm doing a home experiment but it's not going very well. I'm pushing coins on a table. I'm taking the time for how long it takes coin A to hit coin B and then I divide it by the time between them ...
1
vote
1answer
50 views

Speed of liquid being blocked at end of pipe

How fast would water go if at the end of of a 1 inch diameter pipe was closed by a valve? The system is as follows: 5 meter high source of water that feeds a 1 in pipe. The pipe goes straight down ...
0
votes
0answers
32 views

Classical rod-wall-floor system

I have a homogeneous thin rod $AB$. $A$ can slide along $z$-axis, $B$ along $xy$ plane. There is no friction. We have any initial conditions. Now the question is to write down the equation of motion ...
0
votes
1answer
54 views

Friction influencing the motion of a mass and non-inertial frame of reference [closed]

So... recently a Newtonian-mechanics related exercise has raised in me many questions basically ragarding which forces influence a given system and how, I know they might sound bit too "noobish" but I ...
1
vote
1answer
57 views

Is a scaled-up aircraft carrier 'ski-ramp' a viable system to impart enough velocity to significantly assist a spacecraft to orbit? [duplicate]

Not a boost straight up to escape velocity, just sufficient added momentum to make a significant economic saving on fuel cost, mass and complexity of a standard launch. It seems ludicrous to me how ...
16
votes
3answers
1k views

How is gravity consistent when you split an object into multiple pieces?

Here's the picture: In picture 1: Assume that we have 2 objects, namely A, and B. Object A with mass $2M$, and object B with mass $m$; and their distance is $r$. Then the gravitational force of A ...
1
vote
0answers
13 views

Calculating rate of change of momentum for a package [closed]

A helicopter is flying to the right (in the $+x$ direction) with a constant speed $v$, carrying a package of mass $M$ suspended below it using a cable as shown in the figure. (You can assume that $H$ ...
1
vote
0answers
31 views

Finding gravitational potential due to ring [closed]

A point P lies on the axis of a fixed ring of mass M and radius R at a distance of 2R from its centre O. A small particle starts from P and reaches O under gravitational attraction only.its speed at O ...
1
vote
1answer
28 views

How far do atoms move in a wire when whirling it horizontally?

so the question is: I whirl a mass m attached to a wire with length L and diameter d around my head in the horizontal plane. The mass takes t seconds to move around a circle. How far do the ...
0
votes
1answer
30 views

Finding a 1-Dimensional Mass Distribution

Past Discussion There have been a lot of questions and discussions regarding determining the mass distribution of various bodies through non-destructive purposes. Here are a few: Determination of ...
-1
votes
1answer
29 views

A block falling from a height on a block suspended by spring [closed]

The block suspended by the spring is hanging freely and its mass is M. The small block of mass m is dropped on the bigger block from height h. After the small block is dropped 》》》 I want help in ...
0
votes
1answer
60 views

Integrating for speed [closed]

Trying to determine the speed of a falling body with respect to traveled distance and initial speed. I've been provided with the following equation for acceleration as a function of distance and the ...
4
votes
4answers
257 views

Blocks stacked on an incline connected by rope around pulley

Two objects A and B, of masses 5 kg and 20 kg respectively, are connected by a massless string passing over a frictionless pulley at the top of an inclined plane, as shown in the figure. The ...
12
votes
0answers
125 views

How fast would a truck have to go to pull a pedestrian onto the road?

Let's suppose a pedestrian P is walking or standing next to a highway. Suppose a truck T will drive by the said pedestrian at speed V leaving distance L between the two. How fast would the truck have ...
2
votes
4answers
90 views

Deriving $F = ma$ - Newton's Second Law of Motion

Context: In my textbook it is given: 'momentum' short for 'linear momentum': Mass = $m$, momentum is $p=mv$. In time $\Delta t$, momentum changes by $\Delta p$, the rate of change of momentum is: ...
3
votes
1answer
331 views

Two vehicles moving in a line with different accelerations

Let two similar vehicles starting at rest in a straight line (with a distance of $D$ between them) have time-varying accelerations in the same direction. If both of them have similar time varying ...
1
vote
2answers
65 views

How much force is required to compress air?

How much force (Newtons) is required to compress normal air in a chamber to 2 atm? For example, if I had a sealed piston pump, how much force would need to be exerted in order for the air to be ...
1
vote
2answers
60 views

Ice throw from industrial wind turbine

I was watching a documentary where the residents didn't want to have a wind turbine erected nearby. One of the comments from the company was that an ice throw would have very little importance since ...
2
votes
1answer
50 views

Why are non-horizontal levers not considered to be in equilibrium?

Consider a triple-beam balance, like so: An unknown mass is placed on the left pan, and the provided weights are moved on the right until the lever arm comes to rest at an exactly horizontal ...
1
vote
1answer
45 views

Confused with how to approach this pulley problem (solved) [closed]

Question: In the following figure block A has mass m and block B has mass 6.00. The coefficient of kinetic friction between block A and the tabletop is 0.40 The mass of the rope connecting the blocks ...
0
votes
1answer
56 views

Lagrangian for a moving spring device

How can I write the proper Lagrangian for such as system as the one shown in picture? Am confused about what is the suitable way to designate the coordinate.