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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388 views

Why can a ball tossed up object free fall upwards?

I've found many websites that say that a ball tossed upward would be free falling upwards, but none of them say why. If the definition of free fall is an object that is falling while only under the ...
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0answers
117 views

Lagrangian mechanics is different form Newtonian? [duplicate]

I am a post graduate student and had completed my classical Mechanics with Newtonian mechanics to Hamiltonian mechanics. I have better understanding of Newtonian, Lagrangian and Hamiltonian. But I ...
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0answers
98 views

At time $t=0$, what are the magnitude and direction of the perpendicular component of dp/dt? [closed]

In the dark in outer space, you observe a glowing ball of known mass 4.6 kg moving in the xy plane at constant speed in a circle of radius 7 m, with the center of the circle at the origin (< 0, 0, ...
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1answer
80 views

Tangential acceleration [duplicate]

If you are spinning an object using a mass-less string with constant speed in a vertical circle, and when the object is at an angle with the vertical, what happens to the component of weight in the ...
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0answers
78 views

Tension problem for rotating object? [closed]

when an object (tied to a massless string) is moving in a vertical circle with constant speed, does it have tangential acceleration when it is at some angle (theta) from the vertical? I am assuming ...
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1answer
75 views

A shorter impulse-contact period than a rod´s mechanical longitudinal wave propagation period may fail to accelerate the rod?

I have viewed and read several papers related to this subject but cant find any help to understand some seemingly a simple and a straitforward point, about whether a short impulse period compared ...
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0answers
81 views

Which force is necessary for providing centripetal force to a rotating gyroscope?

When a gyroscope is precessing around an axis due to a certain applied torque, if we look at the center of mass , it is going around in circular motion. So there must be some force which provides the ...
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0answers
19 views

If a nozzle that converges from an inside diameter of 5cm to 3.5cm carries a gas at a VFR of 0.10 m^3/s, what is the change in average velocity? [closed]

If a circular nozzle that converges from an inside diameter of 5 cm to 3.5 cm carries a gas at a volume flow rate of $0.10 m^3/s$, what is the change in average velocity of the gas? (A nozzle being a ...
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0answers
77 views

Maximum friction force for a wheel to be able to roll

The wheel with mass $M$ and radius $R$ below is free in space (it is not on the ground). A torque $\tau$ is applied to it through an engine. A horizontal force $F = \frac{\tau}{R}$ is also applied to ...
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2answers
174 views

Loads in decelerating a falling object

I remove trees in confined spaces setting up rigging systems, I am keen to look at the science behind it in more depth so far the formulas that I have found don't take into effect the ongoing effect ...
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1answer
399 views

Spring Powered Car - Which Design Is Best? [closed]

I'm in the preliminary stages of building a spring powered car to race over a distance of 10 metres. It is a yearly event held in my local area and so far we've only seen one spring powered car. I ...
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0answers
602 views

Tension Problem: Solve for T for two sliding blocks connected by a string [closed]

The problem: Two blocks made of different materials connected together by a thin cord, slide down a plane ramp inclined at an angle θ to the horizontal as shown in the figure (block B is above ...
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2answers
50 views

Diagram of forces exerted on objects

Assuming that there is an interaction between 1 and 3 (they attract each other), what are the forces between 1 and 2? I know it is as if the force acts on a different body (1+2), but I want to know ...
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0answers
45 views

Elastic Collision [closed]

A cube has a side length of 20 cm. An atom in the gas moves around the cube as shown. It continually bounces off the four lateral walls of the cube. The atom has a mass of 6.6×10−27 kg. Because of the ...
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1answer
221 views

Question about torque and center of mass [duplicate]

If a yo-yo's string is not attached to anything and the yo-yo is dropped, it is obvious it will fall at $g$. In this scenario, Tension of string = 0. If a yo-yo's string is attached to a cieling and ...
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0answers
32 views

Collision (work energy and power) [closed]

A ball is allowed to fall from rest on a horizontal floor from a height of 10m If there is 20% loss of energy due to impact then after one impact ball will go upto?
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0answers
47 views

Calculus of variations applied to a rotating liquid

I thought I knew how to use calculus of variations, but then I started thinking about the problem of a rotating liquid and it confused me a great deal. It would be nice to hear your thoughts on the ...
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0answers
75 views

Show that the profile of the hill is a cycloid [closed]

I'm struggling with this problem: From George Simmons_ Differential Equations I've tried different things and I showed that the $x$ component and the $y$ component of the shadow should move with ...
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0answers
34 views

Length of the missing part [closed]

I have got a very interesting question. A car is driving this way on the picture down. In the looping is a missing part. The radius of the looping is r = 40cm. The car starts at the height h = 3r. If ...
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0answers
34 views

Similarity in two events from Dynamics point of view [closed]

What is similar from dynamic point of view between book lying stationary on horizontal table and rain drop falling down with constant speed? I can find two similarities Force acting on them is ...
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0answers
307 views

What is the angle of projection when at maximum height the speed of a projectile is half the speed at half the maximum height? [closed]

I have been struggling with this problem: The speed of a projectile when it reaches its maximum height is one half of its speed when it is at half its maximum height. What is the initial ...
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1answer
127 views

Reduced mass and harmonic mean

In two-body problems, a reduced mass has the form: $\frac{m_1 m_2}{m_1+m_2}$, which by appearance, is half of the harmonic mean of $m_1$ and $m_2$: ...
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1answer
49 views

Angular Momentum Conservation Definition [duplicate]

Did I missed something in angular momentum definition? Two identical bodies rotate around mass center. Now I invented anti-gravity and turning gravitational switch off. Those two bodies will move now ...
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0answers
38 views

How forces work during hammerthrow

I am not sure if I understand how forces work during hammerthrow. From my understanding athlete works with Fmuscle force on a ball and rotate it and a ball works with equal opposite force on an ...
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0answers
29 views

At what speed (km/h) are the ride-goers (harnessed at opposite ends of ends of “propeller”) travelling? [closed]

The Revelation is one of the fastest and most exhilarating extreme rides in the world! Designed like a giant airplane propeller, the Revelation holds two to four riders comfortably in the cockpit ...
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0answers
48 views

Make an Electric motor work with help of 4 magnet wheels? [closed]

I am working on a car prototype that should work on the electricity that it generates with the help of magnets. The strong magnets will be fixed at the wheels. A Coil of thin copper wire(solenoid) ...
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0answers
88 views

Inclined plane problem with friction [closed]

A block of mass 6.0 kg slides from rest at a height of 2.0 m down to a horizontal surface where it passes over a 1.5 m rough patch. After crossing this patch it climbs up another incline which is at ...
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1answer
102 views

Rational ratio of frequencies leads to isolating integral of motion

Padmanabhan's discussion of dynamics mentions that in general the two dimensional harmonic oscillator fills the surface of a two torus. He further notes that there will be an extra isolating integral ...
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0answers
27 views

Static Friction on a Circular Road [duplicate]

I was recently brushing up on my dynamics, when I saw the interpretation of how a car moves in a circular road. Apparently, the car can stay in a circle due to static friction acting inwards. But I ...
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0answers
73 views

Max speed as a function of engine power

My question started out as finding the maximum speed of a go kart, taking into account only the drag forces as force opposing the motor. I've done some investigation to find: $$ F_{drag}=\; ...
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1answer
154 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 ...
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0answers
87 views

Is mechanics needed in order to learn electromagnetism? [closed]

I'm a college student who wants to learn physics. I want to get started with electromagnetism as soon as possible. Is it okay to skip over mechanics, or is mechanics a big requirement before starting ...
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0answers
180 views

point-particle vs rigid-body [closed]

As pointed out here point-particle-based modeling can lead to very inaccurate predictions. Could you give an example where point-particle-based model describes reality accurately enough and one where ...
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0answers
67 views

How to find the force to cause certain trajectory? [closed]

So I got a little board today and decided to do some physics. What I came up with is confusing me alot. Say someone throws a rock and when this happens you get the known's of. From here is there a way ...
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1answer
222 views

Does a pivot exert an additional force, normal to the centripetal force, on an object rotating about it?

A thin plank of mass $M$ and length $l$ is pivoted at one end. The plank is released at 60$^{\circ}$ from the vertical. What is the magnitude and direction of the force on the pivot when the plank ...
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1answer
362 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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0answers
18 views

Is acceleration quadratic or linear outside of a gravity field? [duplicate]

So as I understand it: If you hit a wall at twice the speed you hit four times as hard? I often ask people this and everyone says "at twice the speed you hit twice as hard". $K=\frac{1}{2}mv^2$ is ...
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0answers
135 views

Question about Atwood Machine and Changing Masses

Say we have an object of X Newtons on the ground called object 1, and it is connected to another object called object 2. If we change the mass of object 2 in intervals until object 1 < object 2, ...
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0answers
77 views

Forces and acceleration due to an angle that varies over time [closed]

I'm having difficulty figuring out how to set a problem up. The problem is as follows: A $5\ kg$ block is being pulled along a frictionless floor by a cord that applies a force of constant magnitude ...
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0answers
43 views

Calculating size/weight of the base of a banner to withstand wind load [duplicate]

I want to build what is essentially a banner - a rectangular piece of fabric that will be mounted to a stand and displayed vertically. This object will be outdoors, so the most important factor in it ...
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0answers
68 views

Tension on an object [closed]

According to a website, $T_3 = T_2 + T_1$. Also, the rope and pulley device are mass less. But I don't really understand this. Let me try and explain how I see the problem. $M_2$ receives tension ...
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0answers
45 views

Three equal mass points on the string [closed]

Help me please to solve my problem. I have three equal point masses on the line string. $L$ is a distance between masses. $P$ is a pulling of the string. I know that the potential energy of that ...
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1answer
57 views

Throwing ball against oily/slippery wall

I would like to know whether a ball bounces back normally if you throw it against an oily wall. Like a wall watered down with oil. Basically I want to know if it will actually slip before bouncing ...
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1answer
911 views

Block and Pulley Problem with Friction [closed]

1.) What is the acceleration of the hanging mass? (Indicate the direction with the sign of your answer.) 2.) Determine the tension in the cord. (Indicate the direction with the sign of your ...
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0answers
121 views

Friction force problem for a 4 wheel drive Car [closed]

The car is a 4 wheel drive in equilibrium, the car doesn't touch the ground with the front wheel (A) but is in contact in B with the sidewalk (the sidewalk has a hight equal to $h$), the friction ...
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1answer
79 views

Height of rebound of a projectile from a sphere

My work here is: First, I use conservation of energy: (taking the plane as zero potential) $$\frac{1}{2}m(\frac{2ga}{5})+2amg=\frac{1}{2}mv^2+a(1+\cosθ)mg$$ ...
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1answer
40 views

Finding the equation of motion regarding a block pulling a uniform disk [closed]

My problem is finding the equation of motion for the block. Using Newton's Second Law, I did: $$4g-T-R=4\frac{dw}{dt}$$ But the mark scheme says: $$4g-T-R=0.2*4\frac{dw}{dt}$$ And I don't understand ...
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1answer
163 views

Reducing Friction between 2 abs plastic bodies [closed]

Here at the company we've been working on a new product, and it will more than a few times a day and with a considerable force, slide on a plastic surface, being itself, another plastic body, roughly ...
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0answers
44 views

about MS in Theorectial Physics [closed]

I am an undergraduate student (Bachelors of engineering) about to complete my 1st year in the field of Information science and engineering or information technology. I am interested in pure physics ...
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0answers
106 views

Bernoulli's equation

So there's a pipe filled with water that has 4 other pipes with same radii connected to it. The question is to arrange heights from the smallest to the biggest level in it. $A_1$ and $A_2$ are ...