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
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4answers
93 views

Rotating the bucket in circular motion without spilling water

In the bucket experiment when the bucket reaches the top of the circle why will it have a normal force acting on the water downwards? Doesn't normal force oppose any other force? There is no force ...
0
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0answers
15 views

Impulse of two different objects

I was running over a question, A collision occurs between particles A and B which are moving in opposite directions in the same straight line. The impulse on each particle in the collision is 2N.s, ...
0
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1answer
24 views

A body acting by zero net external force

I wonder, for a rigid body, if the vector sum of all external forces acting on it equals zero (Fnet = 0), does it also leads to the vector sum of all external torques acting on it about any point ...
2
votes
2answers
22 views

Force against mg when block is connected to block and held horizontally

In the image attached, what would be the force that would balance out the gravitational force $mg$? The block is also not accelerating downwards so there should be some force acting on the block to ...
1
vote
1answer
32 views

Interaction Potential for Damped Driven Pendulum

I'm trying to use the velocity Verlet integrator to simulate a damped driven pendulum (with unit mass) described by $\ddot{\phi}+\gamma \dot{\phi}+\omega_0^2 sin\phi=Acos(\Omega t)$ The Verlet ...
-2
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1answer
21 views

Mass is put on top of springs in series. Acceleration between springs? [on hold]

I am quite stuck with following problem: Two springs are in series. Let's call them spring 1 and spring 2. Spring 1 is connected to ground. Springs are connected with each other. Mass is added on top ...
3
votes
1answer
47 views

Collision between a “spring” and a particle

I am currently attempting to create a simple 2D physics engine, and I just need to know how to solve a certain collision. I have particles, and between any two particles, springs can be connected. ...
21
votes
6answers
4k views

Supergun Launching of Satellites

I should say first that I don't believe this is a feasible launch method, otherwise NASA and other space agencies would be using it by now. It's based on this BBC news story Saddam Hussein's Supergun ...
12
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3answers
1k views

Energy needed for Superman to take off and fly at the speed of sound

I just watched "Man of Steel", and I'm wondering if my logic is correct. Let's assume Superman is 80 kg. The energy required to take off from the rest to reach the speed of sound in air (if I neglect ...
1
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2answers
205 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, ...
-5
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0answers
18 views

Calculate Pendulum force [on hold]

I would like to calculate the impact force of a free fall 16kg Pendulum ball hitting the wall at 1.5m away. Please help. Thanks
1
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2answers
69 views

Newton's Cradle: why does it stay symmetric? [duplicate]

How is it that always the same number of balls leave at the other end in Newton's cradle. I understand that the momentum needs to be conserved, but as momentum is defined as p=m*v couldn't you have a ...
1
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1answer
282 views

Rotating platform with pulleys and stacked blocks

This was a practice test question. Consider the following figure. (If the frictional coefficients are unclear, between A and B we have $k_1 = 0.3$, B and platform is $k_2 = 0.2$. If you further ...
0
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1answer
15 views

External and internal resistance to airflow

If an aircraft was travelling at 100mph an hole was opened to allow 100mph into the cabin,then the airflow is feed into an amplifier like a ramjet and the airflow out of the ramjet was increased to ...
0
votes
1answer
55 views

Springs, elastic potential energy, kinetic energy

If a ball with some kinetic energy collides with a spring, the ball doesn't lose its kinetic energy in an instant, right? it loses kinetic energy as the spring gains potential elastic energy. Right? ...
-2
votes
0answers
31 views

Pendulum acceleration vector [on hold]

I'll make this quick, I want the acceleration vector for a pendulum WITHOUT using angle acceleration and angle velocity, just using the tension and gravity forces. I tried to use the formula for the ...
-2
votes
1answer
27 views

Dropping a bolt in an accelerated lift [on hold]

Here's the problem given to me: A lift starts from rest with an acceleration of $a$. At the time it starts, a bolt is dropped from the top of the lift. If the height of the lift is $h$, find ...
-3
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0answers
31 views
43
votes
4answers
7k views

Why would a spinning space station create a centrifugal force on an astronaut rather than simply spinning around him/her?

We often see films with spinning space station that create artificial gravity by having the astronauts pulled outwards by centrifugal force. I'd like to know if this would really happen, and if so, ...
6
votes
5answers
9k views

If a space ship accelerated constantly, would its astronauts constantly feel the forward movement?

I know that if a space ship suddenly traveled very fast, its astronauts would be fly against the back wall, potentially getting hurt. If the space ship suddenly stopped, they would also fly against ...
5
votes
3answers
669 views

Rocket launch from a mountain

If we were to build a high speed rail up the side of a mountain like in some Science Fiction movies, what is the velocity needed at the point of leaving the mountain excluding angular momentum from ...
1
vote
1answer
207 views

Can two bodies of different mass attached at ends of string passed over a frictionless pulley produce equal tension on both sides?

In my textbook there is given a case that to calculate acceleration and tension produced in string when string is attached at it's ends with two bodies of masses such that $m1>m2$ and the tension ...
2
votes
1answer
45 views

How can you find the impact necessary to change the direction of Earth's spin?

If an object the mass of the moon was to hit earth's surface at an angle that would be in the opposite direction of earth's spin, how can you find how much momentum the object needs to cause earth to ...
1
vote
2answers
62 views

Model/formula for bouncing ball

I'm programming an animation of a bouncing ball, and I want it to be as realistic as possible. I fully understand the physics while the ball is rising and falling: It accelerates downward at 9.8 ...
3
votes
2answers
1k views

Average Force vs Net Force

The F in $$Impulse = F*t$$ is said to be the average force. For a ball dropped vertically onto a horizontal surface, the average force, F, on the ball from the floor is: $$F = \frac{\Delta{p}}{t}$$ ...
3
votes
3answers
272 views

Why does earth have a minimum orbital period?

Using the equation for Kepler's constant for Earth $K$: $$K = \frac{GM}{4\pi^2}$$ $$K = 1.01 \times 10^{13} \;\rm m^3/s^2$$ Finding time ($r = 6.4 \times 10^{6} \;\rm m$ (radius of Earth)): $$K = ...
0
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3answers
2k views

Pendulum in Accelerating Elevator

I have been looking for this for quite some time now. A simple pendulum behaves in SHM. Let's put that pendulum in an upward accelerating elevator. The component of the force that acts in SHM ...
2
votes
1answer
33 views

Find force centroid from forces and moments [closed]

A force $\vec F = (F_x,F_y,F_z)$ is applied to a point that its position vector is $\vec r = (x,y,z)$ generating a moment $\vec M = (M_x,M_y,M_z)$. Find position vector of the point ($\vec r$) if ...
2
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0answers
35 views

Barycenter correction for inner planets in solar system?

I want to run simulations of the solar system, and I've read in some papers that to speed up the simulations it is useful to use the barycenter correction of the inner planets (from Mercury to Mars), ...
0
votes
2answers
110 views

How the standard units for length force and time are defined in US Customary Units as standard units are defined in SI?

I'm much confused about US customary units so I want to ask a lot more questions under single question.First how standard units ,in US customary Units,of force time and length are defined as second or ...
1
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1answer
62 views

Proportional acceleration due to changing density of the Earth

My question has to to do with a recent video minutephysics posted about the time it takes for a person to fall through the earth, found here https://www.youtube.com/watch?v=urQCmMiHKQk At around ...
-4
votes
1answer
49 views

Why do some stars become end up as black holes? [on hold]

The answer involves the gravity and the internal pressure within the star. These two things oppose each other -- the gravitational force of the star acting on a chunk of matter at the star's surface ...
0
votes
1answer
136 views

Can two bodies move with equal acceleration if forces acting on both are unequal?

In my textbook there is a case given that is to find acceleration and tension produced in a string passed over a frictionless pulley and attached with bodies of different masses at its ends. Now below ...
1
vote
1answer
37 views

Accelerations of Cylinders

I got a box hanging from a rope that passes through an ideal pulley that attaches to the superior part of a Cilynder and makes it rotate. An exercise asks me two things: a) determine the magnitude of ...
10
votes
3answers
148 views

Are mechanical energy of an element of a rope and energy density constant in the case of mechanical waves?

I'm confused about energy driven by a wave. Consider a sinousoidal wave moving in a rope. In my view each element $dm$ of the rope follows a simple harmonic motion in time. That means that the ...
-3
votes
0answers
14 views

Does anybody know how much heat an otto ic engine produces? [on hold]

When the engine is working, it produces torque(useful) and heat(not really). Does anybody know the proportion of torque/heat an average gasoline engine produces? Thank you.
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1answer
28 views

Calculate the average force exerted by the bat on the ball [on hold]

A cricket ball of mass 150 g is moving with a velocity of 12 m/s and is hit by a bat so that the ball is turned back by a velocity of 20 m/s. The force of blow acts for 0.01 second on the ball. ...
0
votes
1answer
40 views

Derivation of centripetal acceleration

While reading HC Verma chapter 7 circular motion I came across a derivation which I couldnt understand. I have marked my doubt with red. I don't understand from where +dw/dt [- i sine +j cos0] came ...
-6
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0answers
38 views

What are Black holes exactly? [on hold]

A Black Hole is a very large rip in the atmosphere that opens after to many shuttles have traveled into space. It happens after about 5 million years of shuttles traveling in and out of spaces ...
4
votes
1answer
81 views

Electrons motion

Some days ago, I was reading a very simple text about photoelectric phenomenon (at high school level) that this question came to mind. How do electrons move (for example during their translation from ...
4
votes
2answers
53 views

Analysis of a system consisting of a leaking tank of water

The departure point is this problem: A water tank on wheels is moving over an horizontal trail with negligible friction. There is a small opening in one of the walls, at a depth of $h$ below the ...
5
votes
2answers
700 views

Magnetic field and Newton's third law

If a magnet exerts force on a iron block (opposite and EQUAL), does a iron block also exerts force on magnet (via Newton's third law)? If yes then what magnetic property does it has to produce equal ...
0
votes
1answer
35 views

When a particle oscillates with simple harmonic motion, the period of the oscillation is [on hold]

When a particle oscillates with simple harmonic motion, the period of the oscillation is... a) ...directly proportional to the displacement from the origin b) ...directly proportional to the ...
0
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0answers
48 views

Cavendish Experiment [on hold]

Would the earth’s gravity overpower the gravity of the much smaller and less dense lead spheres? which if this is the case, should equate to no movement?
2
votes
1answer
2k views

Calculating the moment of inertia in bifilar pendulums

I'm an A2 student, and I've been looking into how experimental and theoretical determined mass moments of inertia differ. I came across a method (search Youtube for Measuring Mass Moment of Inertia - ...
12
votes
5answers
9k views

Does it matter how you order your tug-of-war participants?

In a tug-of-war match today, my summer camp students were very concerned about putting the biggest people at the back of the rope. Is there any advantage to this strategy?
0
votes
0answers
26 views

Calculate force required to lift an object to a certain height in a required time [on hold]

This is my first question in stack physics so not sure if I'm phrasing this right. I'm a 9th grade student and this is not a school project. My idea actually. Anyways Say I have a object of weight ...
0
votes
2answers
247 views

We cannot solve this inclined plane problem, right? [on hold]

We drag a sledge along a snow-covered hillside with constant speed. Distance is 150m. The time it takes to reach the top is 300 secs. The sledge is 12kg. And the coefficient of friction $\mu$ = 0.04. ...
0
votes
3answers
327 views

How is the torque reaction in a four-stroke engine produced?

Assuming we have a plane with a propeller driven by an engine like this one . How would the torque reaction be generated if the piston is aligned with the plane center of mass? What I mean is, where ...
3
votes
1answer
40 views

Force and Torque

Think of a uniform sphere. Sometimes if a force is applied to the sphere it does not only move but also spins. So there is a torque. But is it possible to calculate which part of the applied force is ...