Questions tagged [newtonian-mechanics]

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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Dynamics normal reaction homework [closed]

The following is a homework problem which seemed pretty straightforward for me at first. For x movement: $$P\cos{30}=ma$$ $$P=17.32 N$$ However, for y movement, I thought the correct equation is $$...
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A p h y s i c s problem .. .not sure how to do it [closed]

What is the time taken for a body(mass-m) to go down a frictionless parabolic path of width x and height x^2 (the setup is on Earth)?
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Derivation of conservation of angular momentum

I read a derivation of conservation of angular momentum. The derivation used strong form of newtons third law. This was the derivation It was written after derivation that lorentz force does not ...
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What are the equations of motions on a cylinder in ice? [closed]

I have a question about a rotating cylinder in ice. What are the equations of motions in static state and in the dynamic state. I'm especially interested in the friction coefficients. There is also a ...
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Difference between Earth's magnetic field and Earth's gravitational field [closed]

I have a misconception about this. Are these really different? If so then how? And one more problem is that, whether satellites orbit around the Earth because of Earth's Magnetic Field or Earth's ...
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Follow up question of “Why does atmospheric pressure acts on us?”

This question is a follow up question of this one. . I saw the answer by user Thomas Fritsch and he says Actually your head only feels those air molecules which are directly hitting the surface of ...
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1answer
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Limit of Acrylic Rod embedded in a Hole

Let's suppose an acrylic sheet with a hole on it I want to insert something into that hole, let's say an acrylic rod The hole has a diameter of x and the rod has a diameter of x-y. If I increase y, ...
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Foucault pendulum coordinate representation

I have a homework question that boils down to showing that plane of oscillation for a Foucault pendulum rotates 2$\pi\cos(\theta)$ in a day, where $\theta$ is the colatitude angle. I have seen an ...
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Work done as change of potential, how total derivative is converted to partial derivative

I am reading Goldsetein's Classic Mechanics 3rd edition in Chapter 1 it says, If work done in moving form point 1 to 2 denoted by $W_{12}$, is independent of the path it should be possible to ...
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What is the electrical equivalent circuit for this interaction? (Is this correct?) [closed]

A textbook gives an example of an ideal mass striking an ideal string here: This is drawn as an equivalent electrical circuit as follows, where each R represents one of the two string segments the ...
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Is the three body problem always chaotic?

I was reading this recent article in Forbes about the fact that relativistic problems can't be solved exactly. In it the author makes the argument "the two body problem has an exact solution, so all ...
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If The kinetic Energy of a Satellite Orbiting Around The Earth Is Doubled Then: [closed]

(A). The satellite will escape into the space (B). The satellite will fall down on the earth (C). Radius of its orbit will be doubled (D). Radius of its orbit will become half Which Option Is ...
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Why does atmospheric pressure act on us?

I have a bit of misconception about weight which I want to clarify. The air pressure is explained as the weight of the air column above our head acting per unit area. But since air is not continuous ...
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1answer
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Why is the steady speed neglected when calculating work or power? [closed]

A driver notices that her 1080-kg car, when in neutral, slows down from 95 km/hr to 65 km/hr in about 7.0s on a flat horizontal road. Approximately what power (watts and hp) is needed to keep the car ...
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Newton’s second law - a uniform massive rope on a wedge

I am trying to understand this problem intuitively. The wedge accelerates to the left with $a$. According to the solution, the rope on the left must accelerate down the slope with $a\cos\alpha$? And ...
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Does this setup give mechanical advantage?

I've just started learning about pulleys in physics and wondering if below setup offers mechanical advantage. The forces balance nicely but it looks too simple to work. If I pull the rope with a force ...
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What exactly causes particles to drift toward the bottom of a tube in a centrifuge?

As I understand, centrifuges can effectively create gravitational fields that are a thousand times stronger than the Earth's. And it is this pseudo-gravitational force that causes particles to sink ...
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1answer
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How can I find the Final velocity of the System (if perfectly inelastic) Ignoring air resistance [closed]

I am given that a bullet of mass 24.6 grams is shot at a block of 231 grams that will slide on a wooden desk with a coefficient of kinetic friction being .210. all i'm given is that the block more 32....
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2answers
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What is the $F$ force when the object is stationary? [closed]

There is an inclined plane with an angle of $θ$. There is an object on the inclined plane. The forces acting on the object are horizontal thrust $F$, gravity $g$ and supporting force $f$ of the ...
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When a ball hits the wall, the higher the speed of the ball is, the stronger the ball exerts a force on the wall

I am reading an elementary mechanics book and I have the following question now. When a ball hits the wall, the higher the speed of the ball is, the stronger the ball exerts a force on the wall. ...
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How do I obtain the equations for the trajectory of a particle acted by the forces in a vector field? [closed]

Suppose we have a vector field, let's say $F(x,y)=(-x,-y)$ and I release a massive particle in the coordinate $(1,1)$. This particle is going to be acted by a force in the direction $(-1,-1)$ and will ...
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Is it possible to determine the motion of a vehicle moving at a constant speed of $0.8c$?

Suppose you are in a rocket with no windows, traveling in deep space far from other objects. Without looking outside the rocket or making any contact with the outside world, explain how you could ...
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Kinetic Energy in a Conservative Field [closed]

My problem states that $\vec{F}$ is a conservative field, ie: $F = \nabla \phi$ for some scalar potential $\phi$. $$\begin{align}\vec{F}&=m\vec{a}\\ &=m\frac{\mathrm{d}^2\vec{r}}{\mathrm{d}t^...
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In 4 spatial dimensions, would motion under a central force law be confined to a plane?

In dimension $3$, we have the angular momentum $\omega = q \times v$, and since $$\frac{d}{dt} \omega = v \times v + q \times (F/m)$$ from the fact the force is central (so $F$ is parallel to $q$) we ...
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Power of a river

I'm trying to calculate the power of the Mississippi, using the section of the river as it passes through New Orleans. I have the flow rate of a river, turned into a mass flow rate of $16,992,000 \:\...
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Energy-momentum relation in two body collision, dividing vectors

I am in the process of deriving formulas for pair of particles in Center-of-mass frame (CM). I have encountered problem for finding energy-momentum relation. Consider an isolated system consisting ...
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Minimization of energy used to overcome drag

We have an object of mass $1$ kg. How do you push the object $1$ m in $1$ sec under the force $F=-v^2$, so the energy used is minimal? We have to minimize $$\int_0^1\left(\frac{1}{2}a^2+v'(t)*v(t)+v(...
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Lagrangian for a forced system [closed]

Suppose that for a non-forced system Lagrange's equations are \begin{equation*} \left\{ \begin{array}{l} m\ddot{x}+\left( k_{1}+k_{2}\right) x-k_{2}y+2c_{1}\dot{x}=0 \\ m\ddot{y}-k_{2}x+\left( k_{2}+...
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1answer
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Newton third law [closed]

If Newtown third law is true why if l am standing on the fifth floor and l leave a ball it Will not back to and that change from water surface to a rocky surface and the type of the ball makes ...
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Momentum conservation in vertical direction. Confusion [duplicate]

I was solving a problem from "An Introduction to Mechanics" by Kleppner and Kolenkow. The problem says.. A circus acrobat of mass $M$ leaps straight up with initial velocity $v_0$ from a trampoline....
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Ball hits curve of same curvature [closed]

I was doing some physics problems for homework and, while procrastinating, I came up with a theoretical scenario that I couldn't figure out the result of. The following is from a side view and in a ...
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Help with Angular Velocity Problem [closed]

Can anyone help with this problem? I've tried using conventional circular motion, but I can't crack it. My grasp of angular velocity isn't quite good enough to figure it out.
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Is torque imparted onto a swinging pendulum?

I live in a very tall building so I thought it would be interesting to see when my building is swaying by setting up a pendulum. It works great, but I have noticed that over time the tip of the plumb-...
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What's the weight of one thing if it has a constant force of 400 N and passes a road of 200m for the time of 20 s? [closed]

So I had today a physics test and not sure if I my answer is right. It said: "If a body with a constant force of $400 N$ passes a road of $200m$ in a time of $20 s$ and also the gravitational ...
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Torque Question [closed]

I'm really weak at Torque problems, and I do not even know where to start on problems like these. Please help! An automatic screen door closing mechanism works by applyinga force of 25.0 N at a ...
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3answers
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How to check if a given force (in vector form) is conservative or not? [duplicate]

How to check if a given force is conservative or not ? Is there any mathematical way of doing the same?
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What are the effects of centrifugal and Coriolis forces on an object moving in a rotating reference frame?

In a rotating reference frame, we usually come across the following two pseudo forces: Centrifugal force: $f_\mathscr{centrifugal}=-m\omega\times\omega\times r$ Coriolis force: $f_\mathscr{coriolis}=...
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Formal definition of kinetic energy

I'm asking if it is physically reasonable to define formally the kinetic energy of a particle as being a function $T$ that satisfies the following two conditions: $\frac{\mathrm{d} T}{\mathrm{d} t}=\...
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Tensile force applied to a rope [closed]

A golf ball (mass = 45.93 grams) is hanged on a 1/8" diameter, 8 inches long nylon rope that's attached to a metal rod. An amateur golfer hits a golf ball making it spin in the circular trajectory ...
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1answer
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Boost to satellite in elliptical orbit in order to reach the maximum radius? [closed]

If there were a satellite in an elliptical orbit, at what point in its orbit should a booster rocket be fired to kick it to its max radius? I was thinking whennit was closest to the plant/object ...
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Impact of Gearbox on Motor Inertia

If you consider a motor attached to a spur gearbox with a reduction ratio of say $r=50:1$ which is then back-driven so that the motor acts as a generator, what would be the effective moment of ...
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Why should the bulk modulus of a perfectly rigid body be infinite?

Also, what can we say about the Young's modulus and Shear Modulus of a perfectly rigid body and why?
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Tension in a massless string being pulled at its ends with unequal forces

There is a question in my textbook. If a massless inextensible string is pulled on with a force of $10 N$, at both ends, what is the tension in the string? It’s a very common question. The answer is ...
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1answer
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Pressure (gravitational) applied by a hollow, uniform, spherical shell on an object inside it

1) It's a well-known result that the net force inside a hollow, uniform spherical shell is zero at all points. However, for a spherical shell with finite mass inside of it, we say that the mass ...
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Dropping a package from a moving plane with parachute

so i actually need to write a code for dropping a package from an autonomous plane or UAV. the package has a chute attached to it ( and which opens as soon as the package is dropped). the drop ...
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1answer
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Confusion on dynamics/kinematics of a conical pendulum

I have a question regarding the dynamics and kinematics of a conical pendulum. Let's say I rotate a mass on a string so that I make a system that resembles a Conical pendulum. Why does the radius of ...
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3answers
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Simple Harmonic System Equations

Question: Equations: I'm having trouble understanding what a "solution" to equation 6 refers to? What are the implications of including gravity in the equation?
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2answers
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Pressure inside a Hollow (uniform) Sphere

I understand that Gauss' Law (or manual integration) yields that the net force inside a hollow, uniform spherical shell is zero at all points. However, for a spherical shell with finite mass inside ...
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1answer
19 views

Ratio of $F_{net}$ acting on a body to its weight?

The acceleration of a body, expressed as a multiple of $g$, is $always$ equal to the ratio of the net force on the body to its weight. What does this statement mean? Is it referring to the g-force ...
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4answers
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What happens when a weapon breaks on impact?

Here is the situation: You are attacking someone with a wooden pole (such as a pole arm or tree branch). You either (1) hit as hard as you can and the pole breaks into two pieces on impact OR (2) hit ...