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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2answers
75 views

Why is it harder to situp on solid floor?

When I situp on solid floor it is harder for me to lift my body upwards versus on a soft/foamy floor which I can do a lot.
0
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0answers
25 views

Does it cost more energy to ride to the equator comparing to a pole regarding the coriolisforce?

I'm not sure but I thougt when you shoot a bullet from the equator to the north it will cost less energy because the velocity at the equator is higher comparing with places on a higher longitude. So ...
0
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0answers
18 views

Derivation of expression for sagging of a beam [duplicate]

I read in my physics textbook that: A bar of length $l$, breadth $b$ and depth $d$ when loaded at the centre by a load $W$ sags by an amount given by the expression $Wl^3/(4bd^3Y)$ where $Y$ ...
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3answers
62 views

According to Newton's third law the force between two object is balanced when they force exert to each other

According to Newton's third law, the javelin exerts as much force on the athlete as the athlete exerts on the javelin. Would it be correct to say that the javelin does work on the athlete?
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1answer
40 views

A conceptual question about work

Consider an object of mass $5kg$ on a plane. If a horizontal force of $10N$ acts on the object for a time interval of a second. Calculate the work done on the object by the force given that the ...
0
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1answer
63 views

Force, Mass, Motion? $E = mc^2$

Does any object needs force to move? If 'yes', does the matter needs mass to form a force? These questions arises from me because $E = mc^2$ and $F = ma$ does not relate and one does not agrees with ...
0
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1answer
69 views

Is the acceleration due to a fictitious force independent of mass in general?

Intuitively (at least to me) it seems that the answer should be "yes", since a fictitious force arises due to being in a non-inertial frame; the frame is accelerating, but the objects within this ...
0
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1answer
34 views

Infinite acceleration of bob in pendulum with no friction or air resistance

So i'm a bit confused about something. If we take a mathematical pendulum and we apply a force to it. We ignore all friction and air resistance and only consider gravity and the force applied to bob. ...
0
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1answer
45 views

What role does the center of mass play in this situation? (electric potential)

Four masses $10\ \mathrm{g}$ each are tied together by $10\ \mathrm{cm}$ strings to make a square as shown. Two of the masses carry a charge of $2\ \mathrm{\mu C}$. The string between the two ...
0
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1answer
42 views

Angular Acceleration of a Pendulum

I am trying to work out the mathematics behind the design of an old mechanical brake tester. The device sits in the passenger foot well of a vehicle and tests the brake efficiency. The device is ...
-1
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1answer
48 views

quantum entanglement and its application in migratory birds [closed]

Explain the concept of quantum entanglement.Also explain its application in migratory birds. i know that it also has a relation with the magnetic field of the earth.
0
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0answers
21 views

Plot current-voltage curve

I have been given the following question as part of an investigation for my Applied Maths course: "[...] Then construct the current-voltage curve, i.e. the dependence of $\left< \dot{\theta} ...
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1answer
38 views

Is Momentum conserved in this block-wedge system?

There's a block slides downward along a frictionless wedge which sits on a frictionless horizontal surface, when the block leaves the wedge, both of the wedge and the block have a horizontal velocity ...
0
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1answer
45 views

Force of baseball bat given force of ball and recoil distance

Say I swing a baseball bat and hit a ball. The ball is moving at 60 miles per hour and impacts the baseball bat squarely at that speed. The ball has moved twenty feet before impacting the bat. The ...
0
votes
1answer
38 views

How does distance affect force?

In the image below, the system is in equilibrium. Some force is applied at the bottom of the vertical pole and is being opposed by some force at the top by the horizontal pole... But I feel as though ...
0
votes
1answer
16 views

Finding the force exerted by a mass at different contact points

Okay so I've been doing a math assignment on torque which has to have real-world applications so I've gone off on a massive tangent trying to incorporate physics principles and trying to get them as ...
0
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1answer
40 views

Angular momentum consevation and central force

A circular orbit of radius $a$ passing through the centre of a central force is given by the equation $r=2a\cos\theta$. Then using the orbit equation one can show that the force varies as $\vec ...
0
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1answer
15 views

Physics of Auto Crashes and Airbag Modules

I recently saw a post (that was pretty old) asking why we don't consider the jerk function more often in sciences that deal with impacts or sudden accelerations. The general belief was that impacts, ...
1
vote
1answer
41 views

How to explain gyroscopic precession in a more intuitional way?

When Studying the phenomenon of precession a classic example installation is this: a wheel spins around the Y axis, gravity applies and the upper part starts spinning around the Z axis. The textbook ...
3
votes
2answers
54 views

Does inelastic collision say the ball bounces back to you when thrown at an angle on ground?

I created a bounce simulation using exactly the formula from Wikipedia. The behavior I observe is not what I would expect in two cases: When two balls hit off-centre, they act the same as if the ...
1
vote
2answers
72 views

Solving Projectile Motion Equation with Drag [closed]

Previously, I was helped in solving a projectile motion equation to model the velocity of the projectile with respect to distance with drag taken into account by using differential equations (which I ...
0
votes
1answer
37 views

What is the translational velocity of a sphere after rolling down a hill?

A solid, uniform, spherical boulder starts from rest and rolls down a 50.0-m-high hill. The top half of the hill is rough enough to cause the boulder to roll without slipping, but the lower half is ...
4
votes
2answers
72 views

The two causes for the factor 2 in Coriolis effect

While reading this document on Coriolis effect http://empslocal.ex.ac.uk/people/staff/gv219/classics.d/Persson98.pdf, I saw the followig sentence Two kinematic effects each contribute half of the ...
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2answers
55 views

How does conservation of energy work?

I understand that the law of conservation of energy states that energy cannot be created or destroyed, it can only change from one form to another. This means that the total energy before a certain ...
0
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3answers
78 views

Zero Potential Energy Change in Raising a Mass

Suppose I am able to lift a body of mass $m$ up using a constant force $F=mg$ so that net acceleration is zero on it. I want to find the potential energy and the total energy of the body when I have ...
0
votes
1answer
18 views

Max theoretical efficiency of a weight powering a car [closed]

Say we had a 700 gram car. There is a 2 kg weight on a launcher that is supposed to power it. What is the maximum theoretical speed it takes to travel 8 meters? Its a little hard to describe so ...
0
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1answer
22 views

Objects rotating and rolling without slipping

The question below confused the hell out of me. It's pretty much straight forward but until the point of where to use which radius. I know that I'll have to use the formula Tr=Iα and then we simplify ...
0
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1answer
20 views

What is the velocity vector of a spinning hoop as view from the ground?

Original Question: I've calculated a) and b) My issue is with parts c) and d). I understand that v= 1.56 m/s for the translational motion and that the velocity vector should be the sum of the ...
0
votes
1answer
18 views

The change in gravitational potential energy of a meter stick that swings through the vertical starting at rest from the horizontal

Full question: My attempt: So I tried $KE = \frac{1}{2}I\omega^2$. Since this was a meter stick, I calculated $I = \frac{1}{3}mL^2 = \frac{1}{3}(.180 kg)(1m^2) = .006\;kg m^2$ Then I attempted ...
0
votes
1answer
27 views

How does the total change in energy being negative indicate the direction of the Force?

To be more precise consider the following situation: Suppose a satellite is orbiting at a distance of $r_1$ from the centre of the earth. After some time, rockets are fired such that the new distance ...
3
votes
2answers
195 views

Climbing Stairs and Calories Burnt

I climb stairs to work (20 floors) every day . The least amount of work my body is doing by gaining potential energy (P.E) = mgh where m is mass , g is acc. due to gravity and h is height . Assuming ...
1
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1answer
36 views

How a particle moves against a pressure gradient?

This is a photo of a compressor together with a diffuser. These engine parts convert the kinetic energy of the air to static pressure and supply air to internal combustion engines. The somewhat ...
0
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1answer
23 views

A person on a concrete slab on a frozen lake starts walking $ 2 m/s$, what is the speed of the concrete slab? [closed]

Full question: My attempt: Let the M be the mass of the person. Let x be the length of the slab. The original center of mass is $\frac{5M\frac{x}{2}}{M + 5M}$. Let's say the person walks a ...
0
votes
1answer
27 views

Two bodies connected to each other with with a string of lenth L is a rigid body? [duplicate]

Suppose we have two bodies A and B, they are connected to each other with an ideal string of length $L$. Then is this system a rigid body? This system has 5 degrees of freedom ( 6-1 constraint). But a ...
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2answers
36 views

Definition of translational , rotational , rolling motion

What are the exact definitions of pure translational , pure rotational and rolling motion ? I am a class 11th student ... I find it difficult to exactly make a difference between translational , ...
0
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0answers
21 views

Force conversion in a barrel cam-follower mechanism

A barrel cam-follower mechanism consists of a (cylindrical) barrel with a cam track, a cam-follower (roller) inside of the track, a fork connected to the cam-follower and a guide along which the fork ...
0
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2answers
51 views

Problems with work on an inclined plane

A constant force $F_a$ of magnitude $82.0N$ is applied to a $3.00 kg$ shoe box at angle $53.0^{\circ}$, causing the box to move up a frictionless ramp at constant speed. How much work is done on ...
0
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2answers
48 views

Pressure exerted by ideal gas on walls of container

All derivations I've come across are more or less similar to this: All of them take total momentum change as $2mv_{x}$ and divide it by total time to get the force exerted on the wall. That seems to ...
1
vote
1answer
31 views

Orbiting in space (free fall) and centripetal force?

So basically astronauts are weightless b/c they are free falling. But to get to that state they need to be moving real fast. So why doesn't that speed along with the centripetal force affect them? I ...
1
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4answers
67 views

Question related to accleration due to gravity [closed]

What effect will be seen on the value of accleration due to gravity if radius of the earth is decreased keeping the mass constant?
0
votes
1answer
50 views

Hard drive disk seems to “move” its weight when running

I have an external box for hard drives and plugged a broken hard disk to it. Then I turned it on and took it in hand. Now, if I gently tilt and turn the box on its axis, the weight seems to "go" in ...
0
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2answers
45 views

Question about aircraft/rockets

Lets say that you're sitting an inverted airplane. How do you determine how fast the plane must accelerate in order for you to not fall out?
0
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5answers
177 views

Why do heavier objects fall faster on hills but not in straight drops?

All other things being equal, if a heavier object will roll at a higher speed down hill than a lighter one, because it's heavier with more mass, then how is it that dropped objects fall at the same ...
0
votes
2answers
38 views

Position, velocity and acceleration vs time graphs

I'd like to draw graphs of a vehicle and I have a position vs time table. I can set the points but how am I supposed to join them, straight or hyperbole ? If the object is accelerating which is yes ...
0
votes
1answer
27 views

Effect of Coriolis force

Is Coriolis force fictitious in an inertial frame or not? If so can it be mathematically deduced using an inertial frame as reference?
2
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1answer
99 views

Why can't I use conservation of energy to find ratio of final velocities on different planets?

The question is An object of mass $m$ is allowed to slide down a frictionless ramp of angle $\theta$, and its speed at the bottom is recorded as v. If this same process was followed on a planet ...
0
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2answers
30 views

Why does limiting friction have to act when a block tied to a wall is pulled?

A block lying on a rough surface, is connected to a wall by a mass less, inextensible string and an unknown amount of force is applied to the block opposite to the side of the wall. Now, if it is ...
11
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7answers
1k views

Why doesn't an object, despite having a non-zero potential energy stored in it, fall by itself from the elevation?

When an object is at a certain height, it has some energy stored in it as we have done some work on it to get it to that height. So when it already has energy, then why doesn't it fall off from the ...
0
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2answers
32 views

Is the difference between getting hit by an object connected or disconnected to the excerting source of force negligible?

This article is facing with the impact of a single lightsaber in the mideavel time. And in the comments of this answer I was explaining that I would expect the disconnection from the blade by beeing ...
0
votes
1answer
29 views

Why does the water in a bucket stay even when swung around in circular motion? [duplicate]

What are the force that act on the water and which force is responsible to keep the water from falling out?