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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What force needs to be applied to produce twice as much acceleration as already present in a body?

Let the current body of mass $m$ be moving with acceleration $a$, produced by applying $F = ma$. So, I thought that if I apply force $F$ again (same magnitude and direction as before), I would get ...
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3answers
65 views

Why is a beam reach the fastest point of sail on modern sailboats?

I've heard that a beam reach (perpendicular to the wind) is the fastest point of sail on modern sailboats, but I haven't heard a satisfying explanation of the physics behind the claim. Triangular ...
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0answers
47 views

Please explain the integration [on hold]

the integration of (6 - 0.06s) should be (6s - 0.03s^2). Why is the solution (12s - 0.06s^2)? It seems its factored by 2 but I don't know the explanation to it. Cheers
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0answers
10 views

simple question on torques on an ellipsoid

I have an ellipsoid, and in the reference frame where the x-, y- and z-axis are aligned with its eigenvectors I compute the torque $\vec\tau$ acting on it. And I'm asking myself how can I quantify ...
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3answers
149 views

Forces and acceleration on rotating objects?

Suppose you have an object undergoing uniform circular motion, with force vector pointing towards the center and another force vector tangential. Can it be said that the net force pointing in the ...
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2answers
37 views

Connection between moment/torque and centre of gravity?

So I understand how moments work with regards to basic examples like pushing a door, in that the further you are away from the hinges of the door, the greater the moment, which is like a turning ...
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1answer
35 views

Distribution forces

I've got two trees and between them is a rope. When someone about 100kg sits at the center of the rope, what are the forces on both parts of rope (to the left-hand side from the person and right-hand ...
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1answer
26 views

What does a scale accelerating on an incline read?

I was watching an online video lecture about dynamics, and then I came across this brain teaser, and I've been thinking it over for a couple of hours but can't seem to find the solution. I hope ...
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5answers
7k views

A force opposing Gravity

Every Action Has An Equal and Opposite Reaction (Newton's Third Law.) If this is the case, does gravity have an equal-opposing force? From asking around I still haven't got a very clear answer; ...
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1answer
571 views

A moving inclined plane with block problem

I'm trying to solve for a challenging problem : a moving inclined plane with a block I want to solve for the acceleration components for the block and the plane and the normal force acting on the ...
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2answers
33 views

Collsion in 2D, find angle and final momentum

Suppose that the collision is completely inelastic. Disregard friction as the surface is smooth. Suppose that one is in the direction of $(1,0)$ and the other $(0,1)$. Is the final momentum the ...
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2answers
72 views

Conceptual question regarding work

Here is a problem I am having some trouble with: The solution is below, my question is, why is conservation of energy valid in this situation. From my understanding, just before the box hits the ...
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0answers
23 views

Why friction increases with increase in normal force? [duplicate]

Why is friction dependent on normal force and not the actual weight? I have also read that friction is horizontal component of contact force. Is this true?
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2answers
458 views

How does this chair move?

I have a chair like this(shown in figure). I was kneeling on the part where we sit. I just gave a sudden push to the part where we rest the back, without moving my legs. I found that the chair is ...
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1answer
446 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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1answer
33 views

Athletics on the moon [on hold]

The moon is a lot smaller than the earth ($\frac{1}{81}$ of the mass and $\frac{3}{11}$ of the diameter). a)How high would a professional vaulter jump on the moon? Assume that he would jump ...
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1answer
31 views

Coriolis Effect vs airplane

So, if I build a highway from north pole towards equator and sit in a car, speed pretty fast towards it, I should feel force with the Earths rotation due to the different rotation speeds of this ...
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0answers
45 views

A question about Undamped Vibration [on hold]

A small collar of mass 1-kg is rigidly attached to a 3-kg uniform rod length L = 1 m. Determine the period of small oscillations of the rod when (a) d = 1 m, (b) d = 0.7 m.
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0answers
18 views

What is the speed of the panel when the spacing between the plates increases [on hold]

Flat-panel capacitor WITH the surface area of $200 cm^2$ is connected to the voltage $1000 V$. One of the plates we start to move away from a constant force $5\times10^{-4}$ Newtons. the spacing ...
2
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1answer
27 views

Force needed to roll wheel over edge [on hold]

I'm looking to find F. See image below. What we know: Mass of the wheel: $ m = 14 $ kg Wheel radius: $ r = 0.32 $ m What I've tried so far: $$ mg + N + \sin(38.7)k = 0 $$ Once the wheel ...
2
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1answer
35 views

If I shoot a hockey puck on ice, is the force of me shooting it applied throughout its travel, or is it a one time force?

For example, if I take a slap shot on a hockey puck, from what I understand, the forces acting on the puck are friction, the normal force, and the puck's weight. And, since I'm not constantly either ...
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5answers
2k views

Kinetic energy vs. momentum?

As simple as this question might seem, I failed to intuitively answer it. Let's assume there is a $10,000$ $kg$ truck moving at $1$ $m/s$, so its momentum and KE are: $p=10,000$ $kg.m/s$ and ...
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1answer
23 views

Greater momentum than initial?

The question is : Heavier object A, initially at rest, is struck by lighter object B. Is it possible for object A to have a larger final momentum than the initial momentum of object B? The ...
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2answers
2k views

Speed of a fly inside a car

A couple of weeks ago I was travelling in a car (120 km/h approximately) and I saw a fly flying in front of me (inside the car, near my nose, windows closed). I wonder how was that possible. Does it ...
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0answers
16 views

pascals law of liquids in terms of kinetic theory of molecules

Suppose a cylindrical container of base area A filled with water is carrying a piston on top. If the piston applies no force on the liquid, assume the pressure is P for a point located on the boundary ...
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3answers
602 views

How can I relate linear and angular motion using a single formula?

I want to relate linear and angular motion using a single formula. Assume I have a 10m rod, and I apply a force of 5N on it, 2.5m away from the axis of rotation for 1s. How can I determine the ...
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1answer
72 views

How to explain this to my sir

We all know that $f = ma$. But for finding displacement, we always use: $$ s = s_0 + ut + \tfrac{1}{2} a t^2 $$ My sir, i don't know why for some reason uses this weird method: $$ F = ...
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1answer
279 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 ...
3
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1answer
171 views

Fluid dynamics tsunami

I have been given a energy head (pressure) in meters for a given tsunami on land. If the tsunami hits a wall 1 meter by 1 meter, is it possible to calculate the height it will reach. I am thinking it ...
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3answers
71 views

in Newtons 3rd law, where does the second body get its energy to react?

A very basic question, and apologies if I have overlooked something obvious. In newtons 3rd law, presumably energy is transfered to the second body from the first body (which itself was subject to an ...
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2answers
447 views

How did Newton discover the universal law of gravitation?

I am having trouble comprehending how anyone could come up with this formula: $F = \frac{GMm}{d^2}$ Could someone walk me through this?
2
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1answer
109 views

Understanding Millikan's oil-drop experiment

This is quoted from A.P. French's Newtonian Mechanicsabout Millikan's oil-drop experiment: The droplets randomly produced in a mist of oil vapor are of various sizes. The ones that Millikan found ...
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1answer
55 views

Why can this question about Centripetal Force not be answered in this way?

Here is the question: "A car travels round a bend which has radius $100 m$ and is banked at an angle of $20°$ to the horizontal. The car is travelling at a speed of $30 ms^{-1}$. What is the least ...
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2answers
80 views

Torsional Spring and Euler angles

I have a question about the moments generated by torsional springs. Consider an inertial reference frame A and a body fixed reference frame B. The frames are connected by 3 rotational springs acting ...
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3answers
168 views

What position of the center of gravity can make the front wheels of the car lift off the ground?

I have a question regarding the position of center of gravity required to just lift off the front wheel of a vehicle Consider a vehicle of mass $m$ having a center of gravity at height $h = 0.5m$ ...
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1answer
13 views

Condition for sliding of two blocks placed one over another and connected by spring

A constant force F is applied to smaller mass till M slides. The spring constant is k. Now it is asked to find k. I'm confused with the condition at which the block will start sliding. Can ...
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0answers
25 views

How to prove by symmetry that tension in a section of rapidly rotating wheel act tangentially?

Suppose a thin uniform wheel of radius $r$ is rotating rapidly about its axis; its spokes have almost negligible strength. According to the book, the centripetal force is provided by the tension ...
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1answer
18 views

Period of a spring in SHM (simple harmonic motion)

An object with unknown mass M is hanged on a vertical spring with unknown spring constant K, the spring is in rest and is 14 cm from its normal point (if it didn't had the mass hanged it had less 14 ...
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1answer
287 views

Acceleration: A ball sliding down the inside of a semicircular bowl

Edit: To clarify, this is a homework question. But I couldn't care less about getting the answer to this specific question as it's not even assigned yet. It looks interesting and I want to understand ...
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0answers
29 views

Action-Reaction pair in case of rocket accelerating in space [duplicate]

I understand Rocket works on Newton's 3rd law. So there has to be action-reaction pair acting on two different bodies. I know rockets accelerate in space, where there is nothing. So now I want to ...
2
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1answer
94 views

If the effects of gravity cannot travel faster than the “c”, does this mean we are only gravitationally bound by masses in our observable universe?

I'm 17 and fascinated by the differences and omissions Newton made in his equations of motion. However it makes sense that gravity can't travel faster than light because of the force-carrying ...
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1answer
55 views

Time to fall in a non-uniform gravitational field

In an uniform gravitational field the loss in potential energy (the work done) by gravity is given by $\text{-}mg\Delta h$ and the time to do so (assuming no friction and no initial velocity) is given ...
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3answers
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First and Second Moment of Mass

I recently came across the definition of the Center of Mass of a system as the point about which the first moment of mass is zero. Further, it defined Moment of Inertia as the second moment of mass. ...
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2answers
43 views

Static friction and Kinetic friction

I can't seem to find this anywhere on the internet or on stack... Sadly. Very basic question: I have a block that is on a surface. The coefficient of static friction between the two is $0.3$, ...
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0answers
12 views

Path of puck through a turntable

I was looking a problem which tells me to consider myself standing on the ground beside a perfectly flat horizontal turntable rotating with constant angular velocity w. Then I lean over and shove a ...
0
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1answer
22 views

Object moving with 2 linear accelerations

Say I have an object moving with an acceleration of 5 m/s$^2$. At a certain point X, due to some forces, the acceleration of the object changes from 5 m/s$^2$ to 2 m/s$^2$. Would this change in ...
0
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2answers
41 views

Best coordinate system for Projectile motion [on hold]

What is the best coordinate system for describing the projectile motion? Rectangular coordinate system or n-t(normal and tangential) coordinate system.
2
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3answers
7k views

Rotating a stone with a string

Suppose we are given a stick and a stone tied to the stick by a string. Now if we rotate the stone around the stick the stone rises in height (see picture below). My question is which force accounts ...
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5answers
227 views

$F=ma$, so if acceleration is zero the force must also be zero?

I was just pushing a huge rock which I couldn't move at all. Given that the acceleration was zero as a result of my efforts, since $F=ma$, doesn't this mean that the force must also have been zero? ...
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1answer
85 views

Projectile, air resistance and wind

So for my school project I am working on a projectile simulator and air resistance. So I have looked at this. Equations for an object moving linearly but with air resistance taken into account? ...