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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3 views

Net force on magnet by fridge

Dylan hangs a calendar on a refrigerator with a magnetic hook. Unfortunately, the magnet is too weak, so the magnet and calendar slide down the side of the refrigerator to the floor with an ...
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5answers
128 views

Why isn't momentum conserved in this pulley problem?

I have some conceptual doubt about method of solving this problem. 24. A block of mass $m$ and a pan of equal mass are connected by a string going over a smooth light pulley as shown in figure ...
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0answers
20 views

How do you calculate minimum speed for a mass to move vertically in a circle [on hold]

For part c) would you subtract the top and bottom tensions to find the minimum velocity. The answer should =2.7 m/s for part c).
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1answer
84 views

Dot Product Force

Konopinski's "What the electromagnetic vector potential describes" (Gaussian dimension) equation (3): $$\frac{d}{dt}[M\vec{v}+(q/c)\vec{A}]=-\nabla q[\phi-(\vec{v}/c)\cdot\vec{A}].\tag{3}$$ contains ...
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2answers
135 views

Advantages of a deadblow hammer?

A deadblow hammer is a type of mallet with a hollow head filled with shot or sand. When you hit with it, say on an anvil, the mallet does not rebound, but just falls flat and heavy. I don't ...
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0answers
26 views

Dynamic coefficient of friction [on hold]

Is there any way or equation or table to find dynamic coefficient of friction between aluminium and asbestos or steel and asbestos in wear tests at various temperatures, pressures and velocities?
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1answer
80 views

Height of Water 'Splashing'

Suppose from a height $H$, I throw a ball of mass $M$ and radius $R$ with initial velocity $u$ into a pool of depth $x$ having a liquid with density $\rho$ and coefficient of viscosity $\eta$. ...
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3answers
133 views

Question about a car on a banked turn with no friction

A popular physics page explaining how a car can make a banked turn even with no friction : gives the following free body diagram and then says In the vertical direction there is no ...
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0answers
31 views

Why does ice fall from the top of the ice tray first?

I haven't found an answer for this anywhere, so hopefully this community can help. It's not important at all that I know this but I'm curious. If you take a plastic tray of ice from the freezer and ...
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2answers
88 views

Coriolis force in free fall: Directions?

Inspired by this Phys.SE question, Coriolis force in free fall, I have to ask: Why does the Coriolis force act in the east-direction? I would say, if I jump from a high distance and look at the ...
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3answers
142 views

Is there a normal downward force here?

Now through my understanding, there is a weight force that points downward on block A, also another weight force that points downward on block B. Between block A and block B, there is two normal ...
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2answers
72 views

Can atoms with top / bottom quarks exist?

Do we have examples in nature or the lab of atoms constructed of 2 top and 1 bottom quark and a tau selectron? How would its properties differ from a hydrogen atom?
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0answers
33 views

Reason for strange magnetic ball movement

I was playing with a set of those neodymium magnet spheres and noticed a couple of strange behaviors (which I believe are related so I'm only positing a single question) and I was hoping to get an ...
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2answers
94 views

Intro Mechanics: Finding ball speeds after collision

So I'm reading about conservation of energy, momentum, balls colliding etc. and unsurprisingly there are hundreds of questions in my textbook where essentially they give me some of the variables (m1, ...
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1answer
398 views

Why does the Nusselt Number for a Constant Surface Temperature, Thermally Fully Developed Circular Pipe Converge To a Constant of 3.66?

I have flow in a pipe with a constant surface temperature boundary condition. The velocity profile is fully developed and the temperature profile is also fully developed. In my textbook, it says that ...
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2answers
50 views

Period of a T-shaped pendulum [on hold]

I'm trying to calculate the period of a pendulum that has a T-shape. For a normal pendulum it's $T = 2 \pi \sqrt{\frac{L}{g}}$ so with $L = 1m$ and $g = 9.8\frac{m}{s^2}$ it's about 2 seconds. I've ...
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1answer
338 views

Tangential and radial acceleration in projectile motion

I'm currently learing kinematics, specifically projectile motion and as an example in my textbook is a bullet fired at some angle. I understand the derivation of formulas to describe that motion and ...
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1answer
58 views

Calculate Spring Constant [on hold]

I am editing the question because it was misunderstood to be a homeowrk question. I am modeling a Stumps equipment for a game called Cricket.Typically the game consists of 3 wooden stumps ...
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3answers
164 views

Animating an Acceleration Vector - Acceleration of object on a crested path in gravitational field

So I was reading in Chapter 3 of my textbook, Sears & Zemanksky's University Physics with Modern Physics by Young and Freedman, 13th Edition, and the discussion took us to a definition of the ...
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6answers
5k views

Difference between torque and moment

What is the difference between torque and moment? I would like to see mathematical definitions for both quantities. I also do not prefer definitions like "It is the tendancy..../It is a measure of ...
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0answers
21 views

Net force when deriving relation between torque and angular acceleration

When deriving the equation $\tau = I\alpha$, it is assumed that $$F_{tangential}=ma_{tangential}$$$$a_{tangential}=\alpha r$$$$\tau=rF_{tangential}$$$$\tau=mr^2\alpha=I\alpha$$ However, doesn’t ...
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2answers
55 views

Vertical Circular motion - Tension and velocity

I read through the question Minimum velocity of the particle at the highest point which is quite similar to my questions. But I still have some doubts in the answers - "The particle will complete ...
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3answers
425 views

Optimal speed for the water wheel

The hydroelectricity plants extract the potential energy of highly deployed massive object (water) as it falls down. Without turbine, all that energy would be converted into speed (kinetic energy) at ...
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0answers
23 views

Finding the potential for a block on a wedge on a slope [on hold]

I'm trying to get the Lagrange equations for a block on top of a wedge which is itself on a slope. We can rotate the system to make it functionally the same as the classic block on a sliding wedge ...
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1answer
59 views

Without friction, what happens in our life? [on hold]

Generally all are subject to friction. So friction is most a essential part of our life, if friction is not available in our surrounding then what would happen in our life and which technique could we ...
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0answers
22 views

Is there a constant decay of particles that maintains the value of the Quantum Vacuum? [on hold]

By my question I am attempting to understand how the Vacuum of space remains at a constant value, (GR the universe on the large scale matches the “critical” energy density of about 8.5×10-10 J/m3) ...
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1answer
24 views

Pulley and block velocity problem [closed]

Block B is moving towards right with velocity 'V'. What is the velocity of block A with respect to block B? Note that the string has negligible mass and is inextensible, also that the pulley has ...
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1answer
43 views

Equation for a physic theory [closed]

There is a theory that state and explains why everything on Earth (or on a place with same force of gravity) falls at the exact same acceleration in vacuum. What's the name of that theory, who came up ...
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1answer
71 views

Why is it effectively impossible to balance this rectangle block on a triangle block? (See photo)

I've always wondered why it's basically impossible to balance a rectangle block on top of a triangle one like this. This is my nine-year-old giving it a try. I have never in my life gotten it to ...
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0answers
26 views

Is it wrong to equate the net force to the force by the spring to find its maximum expansion?

When I want to find the maximum expansion in a spring, let's say connected to 2 blocks of different masses, and some force is applied on one of them, I find their separate accelerations and then ...
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3answers
252 views

Fundamental paradox with Newton's Law of Gravity?

This is my first post here, but I've been struggling with this problem in my head since I studied physics at school when I was 14 (30 years ago!). There seems to be a fundamental paradox with ...
0
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1answer
39 views

The Real Rocket

Suppose we have a Rocket with initial mass $M_o$ and we want to sent it into space. The equation of motion is (i think... please tell me if there is something i forgot) $$\frac ...
0
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0answers
23 views

Need reference on the minimum moment of inertia [duplicate]

I would like to know if there is a book on classical mechanics about the following Moment Of Inertia About Centre of Mass
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2answers
35 views

Horizontal and vertical acceleration of a ball on a slope?

I understand that you resolve the components of the balls weight parallel and perpendicular to the slope in order to calculate the force due to gravity that actually acts down the slope. The ...
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1answer
47 views

What will happen if all the population all over the world jumped together at the same time in sea? [duplicate]

What can happen if a magnitude of such huge force is applied over the sea water of earth? Force applied will be average mass of each person *7 billion *9.8 .
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1answer
63 views

Without using rotational mechanics, why does a gyroscope precess the direction it does?

When a top is spun, it will precess in some direction, either clockwise or counterclockwise. It's possible to find out which way using $\boldsymbol{\tau} = d\mathbf{L}/dt$ and $\boldsymbol{\tau} = ...
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1answer
56 views

Can 4 collinear planets exist?

Imagine 4 planets, A has moon a and B has moon b. A and B are binary planets. Is it possible that a and b and A + B all have same the period, so that the 4 planets are collinear?
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1answer
327 views

Can there be force without motion?

I am confused. Can you have a force or tension without motion? Take for instance two robots with jet packs connected via a cord, each is flying in opposite directions. The tension of the cord is ...
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2answers
42 views

Gravitational force acting on two particles

According to Newton's Laws of Gravitation, $F=Gm_1 m_2/r^2$ So gravitational force F is directly proportional to $1/r^2$. Now if we consider 2 point masses in vacuum at rest at a distance 'd' ...
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1answer
18 views

Stress( Mechanics) [on hold]

The diagram represents a steel tube with wall thickness $w$ which is small in comparison the diameter of the tube. The tube is under tension, caused by a force $T$, parallel to the axis of the ...
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1answer
48 views

Calculating output forces of bicycle wheels

Based on the force on the rear gear $F_t$ and the radii of the rear gear $R_g$ and rear wheel $R_w$ , how would you calculate the force the bicycle exerts on the ground when it is accelerating? I ...
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1answer
100 views

How does ground interact with a box rotating around its corner?

I have some questions about how forces $F$, friction force $F_{friction}$, and normal $N$ interact in order to the box below to turn (clockwise) about the red corner, without sliding. The force $F$ is ...
12
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9answers
8k views

How do you explain spinning tops to a nine year old?

Why don't spinning tops fall over? (The young scientist version) My nine year old son asked me this very question when playing with his "Battle Strikers" set. Having studied Physics myself, I am very ...
2
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2answers
56 views

Why does spinning a golf ball one way make it go further than spinning it the other way?

In golf, you'll often hear people say that one person hits the ball further than another because the one person "draws" the ball while the other "fades" it. I want to know why the direction of ...
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2answers
5k views

Finding distance when the force is a function of time

I'm having trouble with this homework question A mysterious rocket-propelled object of mass 49.0 kg is initially at rest in the middle of the horizontal, frictionless surface of an ice-covered ...
0
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4answers
100 views

Does a flying bullet get KE from gravity?

A projectile P is shot horizontally at 9.8 m/s from a height of 4.9 m, considering no air friction, after a second it will have v = 9.8 m/s on the x-axis and v = -9.8 on the y-axis. Because of ...
2
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1answer
558 views

Relative wind velocity explanation - understanding Irodov problem 1.6

I am having trouble understanding the reasoning behind the solution in this Irodov General Physics problem. The problem is 1.6: 1.6. A ship moves along the equator to the east with velocity vo = ...
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3answers
58 views

How to calculate the linear speed without angular velocity? [on hold]

How would you calculate question (f) the linear velocity, without a angular velocity. The radius of the circle is 0.6m. The answer (linear velocity) should = 1.84 m/s
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0answers
35 views

Altering a model to account for another variable

A question in my textbook asked me to find a general equation for depth fallen by an object of mass $75kg$ thrown from a bridge whilst tied to an elastic rope. Below the bridge there is a stream of ...