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 concepts, use [classical-mechanics]. For Newton’s description of gravity, use [newtonian-gravity].

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Negative or positive newtons

Do we write A car needs 6000N of force to be stopped or A car needs -6000N of force to be stopped
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Why is more difficult to pull a short spring than a long spring?

I guess it has to do with the law of the levers but I am not sure
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Why principle of virtual work gives contradictory solutions depending on the reference point?

An isosceles triangular lamina (ABC) with its plane vertical, rests with its vertex downwards, between 2 smooth pegs P and Q in the same horizontal plane. Show that there will be equilibrium if the ...
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Binary stars orbiting around each other are equidistant

This is a problem that was given to me in my Classical Mechanics course: J.S.Plaskett's star is one of the most massive stars known at present. It is a binary star, that is, it consists of two stars ...
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Physics of Weight-Lifting

I am the Soldier of Steroids and I have a question regarding the concept of "work done" in Classical Mechanics, inspired by my time in real life situation of me the gym (after taking ...
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1answer
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Roll, slip, or bounce?

A sphere is dropped onto an infinite inclined plane. Can we predict whether the sphere rolls, slips, or bounces after hitting the surface? If so, how can we predict this?
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Collision time of two objects

The object $A$ starts motion with constant speed of $u$ as shown in the figure. At the same instant $t=0$, the object $B$ starts motion with constant speed of $v$ by a lateral separation of $L$ from ...
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You hurl a satellite from the space station with a force of 2000 N, applied in the direction of motion, over 1 meter

I wanted to know what speed does the satellite attend with respect to the space station in this situation? Assume mass of satellite = 1000 kg I calculated the orbital velocity of the space station ...
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Intuition on Different SI Units and Squaring Decimals (Beginner Question)

So this is a very basic question. I am certainly not in grasp of some key aspect of physics equations here. I hope someone will be able to help me out. Here is the equation for drag force: $$F_{D}=\...
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A particle of mass $m$ is moving in a straight line and a constant resistance force of magnitude $F$ is exerted on it

a particle of mass $m$ is moving in a straight line and a constant resistance force of magnitude $F$ is exerted on it. If it starts with a speed $V_{0}$ $a)$ How long does it take to stop? $b)$ What ...
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Why do balls bounce in terms of force, momentum and energy?

From what I understand, as a ball is released from some height above a surface, it accelerates downward at 9.81m/s^2 due to the Earth's gravitational field. Once it reaches contact with the solid ...
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My simple pendulum has a period about 1/3 what it should be

I'm a high school science teacher, my primary degree is in Physics, so I have a solid grasp of the background. I'm running into a strange issue with a pendulum lab I had my students complete. We're ...
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Forces in a redirected rope where both strands are loaded

So, if I take a rope, 'fold' it over something to redirect it and then load both strands in the same direction with a certain force, each Strand of the rope should See 50% of the tension, right? But ...
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What rotates a door, torque or force?

I am confused as to what causes a door to rotate. Assume I apply a force to the edge of the door, with the door initially at rest. Force is perpendicular to the door, so it would create a torque. But ...
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What are Kepler's laws in equation form? [closed]

So, I've been studying astrophysics for a while now, and I know about the worded explanations about them. I also know the equation for Kepler's Third law: $$\left(\frac{P}{\mathrm{yr}}\right)^2=\left(\...
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Second order ODE for constant external force

Given a general ODE for damped spring with constant external due to gravity $$my'' + \gamma y' + k y = -mg$$ where $m, \gamma, k, g$ are positive. I have to show that given an initial condition, the ...
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Physicists in Space want to reach his rocket using minimum rope

A man of mass $M$ kg, in space is $L$ units away from its rocket with a hook of mass $m$ kg attached to a mass less rope. What should be the minimum length of the rope so that he could reach his ...
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Oscillation of a square formed by four homogenous bars with mass $m$ and length $l$ [closed]

I came across a problem: Find all non-trivial natural oscillation frequencies for a regular square formed by four homogenous rigid bars with mass m and length l. The neighbouring bars are connected by ...
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Moving an object from a height to the ground at constant velocity, difference between normal vs. applied force

An object is at rest on top of a level surface such as a table at height h. At this condition, a normal force is acting on the object from the surface of the table as well as the force of gravity. I ...
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A person has 2 weighs in his hand, he jumps onto a trampoline and releases the weights. What is the new height the person will achieve?

A person 60kg holds 2 weighs in his hand (30kg each), jumps from a height of 3m and releases the weights as he strikes a trampoline at height 0m, what height does the man achieve after the bounce? ...
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Difference between fixed pulley and movable pulley

What's the difference between the tension and acceleration produced by a fixed pulley and movable pulley? Is there some difference between the direction and magnitude of the tension produced by the ...
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1answer
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Gravitational field in a hollow sphere in the presence of another mass nearby non zero. Why is that so?

I have learned that charges inside a conductor align themselves in an external field such that the net electric field inside them is always zero. My teacher taught me that most concepts of gravitation ...
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Can someone please explain where I went wrong?

A body is starting from rest. A force is acting on it for a short period of time. In that given time, power delivered to it at any instance t is given P = Fv1 = mav1 = mv1^2/t, where v1 is the ...
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What limits the maximum reaction force that can be exerted by the table?

Suppose I have an object placed on a table which exerts a force $$W=mg$$ on the table. The table provides a reaction force which is $-mg$ if the table does not accelerate. However if the table breaks,...
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Differentiating between the formulas for Static and Kinetic Coefficients of friction

With an object sitting at the top of an inclined plane, the static coefficient friction can be calculated with the simplified equation of: μ = tan(θ). In the same way, with an object moving down an ...
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Graph of reaction force of bouncing ball

Let's consider a ball of mass 1kg with initial velocity 8m/s and final velocity -5m/s after bouncing off the floor, the duration of contact with the floor is 0.06s, therefore the average force is 217N....
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Question on force and friction (beginner level)

Please read this question thoroghly. I just want to clear my conception. Suppose I have a mass $M_1$ and another mass $M_2$ on top of $M_1$. Now if I pull M1 with force F ,******the whole system ...
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What amount of force does the average person exert when hammering a nail into an object/concrete? [closed]

I am designing a long reach hammer that can pile nails into concrete that's used for reinforcement and formwork for my senior design project. I just need to know how much force one exerts with a ...
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Simple Harmonic Motion of a particle attached to a spring all inside a circle

I want to understand the following problem: The way I approached this question was using Hooke' Law. I managed to solve for $\lambda$ and later made a differential equation through which I got a ...
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3 block system on a frictionless plane [closed]

3 blocks of the same mass are attached with each other by a massless string. If a force $F$ is applied at one end, then what is the net force on the middle block? [The plane is friction less]
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What if 1st law of motion and 2nd law of thermodynamics contradict?

Assume a large flat surface with a pile of books on it somewhere. Assume this system to be isolated and gravity to be present there. Also assume there to be a flow of time. As now you have ...
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Is this GSCE level, or can it be figured out with GSCE principles, because I’ve got no clue how to approach this question? [closed]

A roller coaster ride includes a circular loop-the-loop. The roller coaster carriage enters the bottom of the loop at $25\mathrm{ms}^{-1}$. The loop has a diameter of $30\mathrm{m}$. The carriage is ...
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Torque in a harmonically oscillating body?

The system oscillates simple harmonically And my question is will the block exert a torque on the rod with respect to the point A? Based on my understanding, Spring 1 and spring 2 both will produce ...
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Rotational equation for variable mass in Simulink/Matlab ignores relative angular velocity of the mass flow?

I am doing a simulation using Simulink/MATLAB. The block I am using called "Custom Variable Mass 6DOF (Euler Angles)". Here is the documentation of this block: https://www.mathworks.com/help/...
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Clearing up my confusion about the static coefficient of friction

I had a question about calculating the static coefficient of friction of an object on an inclined plane (classic physics question). We can simplify those calculations to $\mu = \tan \theta$. Since $\...
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Speed in a friction medium [duplicate]

If a 20 kg object dropped in air has a terminal speed of 60 m/s, what was its acceleration at 30 m/s? I want the answer in steps
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Friction Medium and Terminal Speed [closed]

If a 20 kg object dropped in air has a terminal speed of 60 m/s, what was its acceleration at 30 m/s?
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Why do bullets shoot through water but not through sand?

There are a few questions only on this site about this but none of them answer my question. Can cannonballs go through water? Why does a bullet bounce off water? I find it hard to understand why ...
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Along which axis is the moment of inertia of a harmonically oscillating body calculated?

I have been learning about oscillating bodies and recently stumbled upon physical pendulums. Now the problem is i don't understand about which axis is the MOI calculated while finding the TIME PERIOD(...
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What can go wrong with applying chain rule to angular velocity of circular motion?

Lets say I have a circular motion, like this: I know that: $$\omega = \frac{\text{d} \phi}{\text{d}t}$$ Mathematically, what I am doing wrong, when I attempt to apply the chain rule in the following ...
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What vertical velocity must a projectile launch with to reach a certain height, given a variable gravity?

Let's say we're launching a projectile and we want it to max out at a height of .5g, which, if given Earth, comes to about 9,000 km. (In this, I'm using g as the gravity at the surface, not as the ...
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Are there any books/portions of books/particular topics of study that go into great detail to describe the physics of a rope (or any ropelike body)?

I don't know why, but lately, I can't get the physics of a rope of my mind, specifically what happens to a coiled, or otherwise not taught/pulled straight rope when it is pulled taught. I don't really ...
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How do I find Kinetic Energy when $T$ is not given?

I'm confused about a question given which is briefly: ... full of Cola, places it on the counter top and gives the 2.6-kg pitcher a 8.8 N forward push over a distance of 48cm to send it to a customer ...
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Physics of the Planche

The planche is a gymnastics exercise where the athlete holds their body parallel to ground supported only by their hands. People sometimes train for this exercise using a progression of ``planche ...
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What will happen if both the front wheels of a car are turned in the opposite direction? [closed]

What will happen if both the front wheels of a car of which the front wheels are the wheels which is used for changing direction (I have heard of cars the other way) are turned in the opposite ...
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Calculating travel time of an object on the inclined plane

Let's consider we have frictionless inclined plane and we pushed small object on the plane with initial velocity $v_0$. Travel time while going up can be calculated from following formula: $l = v_0 ...
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Forces applied on a planet

Planets go around the sun in elliptical orbits. The highly exaggerated diagram below shows a portion of such an orbit and the force on the planet at one position along that orbit. The planet is moving ...
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Why are velocity dependent forces considered non-central?

I was going through Classical Dynamics of Particles and Systems (Thornton-Marion, 5ed). On page 50 it is stated: Any force that depends on the velocities of the interacting bodies is considered non-...
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We're supposed to find potential function of the mass two spring system [closed]

I know we want to find the second derivative and evaluate for when Xo is X=0 which should give us harmonic oscillation but I think I'm not taking the derivatives correctly since I'm not arriving at ...

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