The change in position of an object relative to a frame of reference. DO NOT USE THIS TAG just because the question contains motion! Almost all physical systems contains motion. Hence it is often a poor way to classify a question to use this tag.

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5
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2answers
217 views

About photons and mirrors

If a photon hits a 'perfect' mirror (with no environment interference) would the mirror move a bit?
3
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1answer
332 views

Two vehicles moving in a line with different accelerations

Let two similar vehicles starting at rest in a straight line (with a distance of $D$ between them) have time-varying accelerations in the same direction. If both of them have similar time varying ...
0
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1answer
21 views

Shock Absorber - Bus - Not Uniform

Imagine a empty bus/lorry travelling at high speed over the "speed brake", why is that only rear seat is heaved relatively high compared to the fron seat?
0
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2answers
156 views

Different directions of frictional force when objects are rolling

My textbook has two instances of rolling bodies (smooth rolling). In the first, the body is rolling on the horizontal floor with some acceleration of its centre of mass. In this case, the book says ...
1
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1answer
50 views

rectlinear motion with constant acceleration [closed]

Friends, this is a numerical homework problem. I tried my best to solve it but my answer is not matching with the one given at the back of the text book. Please help me out: A motor car moving at a ...
-2
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1answer
39 views

Displacement inside the moving Object

Suppose say a person is standing over the moving bike and he jumps while bike is moving, bike will move forward & person will land in same point at which he jumped, relative to earth position ...
0
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1answer
62 views

Blueshift and increase in energy!

Imagine that there is a car and it is not moving but its headlights are on. There is a wall in front of the car but is very far away. Right now energy is being used only in switching on the ...
0
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0answers
185 views

Inclined plane problem

FOR THE GIVEN PROBLEM AND SOLUTION BELOW 1) The problem statement, all variables and given/known data: A student pulls on a box up an incline of 10 degrees. The student pulls with a force of 180 ...
1
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1answer
60 views

Motion of rigid body system in absense of work

In the absence of work on the system, is there a closed form equation for the motion of a set of constrained rigid bodies (let's say, using Revolute (ie: simple pivot) constraints)? If the bodies are ...
2
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2answers
211 views

Mass Effect on Slingshot Motion?

For my physics class (I'm a high school student), we created slingshots. Our task is to predict the distance a projectile, launched from a slingshot using surgical tubing, would land. We aren't given ...
1
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1answer
51 views

Exertion from swinging on a playground swing

I've read about how by tilting one's body one changes one's center of mass while swinging on a playground swing, and thereby increases the energy of the swing. But I would like to get a better sense ...
1
vote
2answers
116 views

Need clearing up on vector decomposition in motion physics

I've been pursuing physics on my own, and I need something cleared up. Say I have two arbitrary objects, I have their velocities, I know when the collide, I have their normal vectors, etc. I know ...
0
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1answer
79 views

What is empirical mean of centripetal acceleration

We have this formula for centripetal acceleration - $a = v \frac{d\theta}{dt} = v\omega = \frac{v^2}{r}$ but in case of usual acceleration i know that speed in $t_1 = v_0 + a \cdot (t_1 - t_0)$ but ...
0
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1answer
53 views

Second law of thermodynamics and motion

The second law of thermodynamics states that the entropy of an isolated system never decreases, because isolated systems spontaneously evolve toward thermodynamic equilibrium—the state of ...
0
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1answer
109 views

2D. Force applied at angle to body, where translational vector will be directed?

I'm not a physicist and just making some research by the way of creating simple physics simulator, because of that, sorry if this is very dumb question, but I really need help with it. Let's assume ...
4
votes
2answers
142 views

Does $y$-motion really have nothing to do with $x$-motion?

I am watching a Physics 1 for physical science majors on coursera.com, and in one of the concept tests there is a question that goes like this; "A bullet is fired horizontally from a rifle on the Moon ...
0
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1answer
123 views

Does a heavy body move with the slightest force on a frictionless surface?

If I apply horizontal force on a body resting on the ground, my force will be opposed by the frictional force and the body will accelerate at the point where my force exceeds the force of friction = ...
2
votes
1answer
119 views

Problem Of Lazy Fish [closed]

Fish achieve neutral buoyancy (so they don't have to swim constantly to stay in place) via a swim bladder. A swim bladder is a little internal sack that they can inflate/deflate with air, which ...
0
votes
1answer
63 views

Is projectile trajectory on Earth affected by the fact that it isn't a singular point?

So in high school physics, we were told that projectiles traveled in a parabola, but Google searches have said that it's more like an ellipse, since the Earth isn't flat. However, I was thinking that ...
6
votes
1answer
259 views

Two formulas for a particle's acceleration

While on a class my teacher was taking about particle's motion in space. At some point she said the following: Consider that the particle's path is described by a curve in space defined by the ...
-8
votes
3answers
118 views

What would happen if an unstoppable force hits an immovable object? [closed]

I realize that the question a rather large paradox, but I do wonder if such a thing were true what would happen. Assuming that neither of these "objects" can be destroyed by each other.
2
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1answer
105 views

Circular motion problem? [closed]

I am learning about circular motion and not quite sure how to approach this particular problem. Any help would be greatly appreciated! A particle moves along a circular path over a horizontal ...
0
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0answers
90 views

g as a function of Theta

I slide an object down a ramp of a certain length, which is inclined at a certain angle $\theta$. It reaches the bottom in time $t$. Assuming that no forces act on the object other than gravity and ...
2
votes
1answer
104 views

According to Newton's third law, why don't Action and Reaction make equilibrium? [duplicate]

According to Newton's third law, Action and Reaction are equal and in opposite direction. If both forces are equal and in opposite direction then why they don't make equilibrium and void the effect of ...
0
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1answer
1k views

Projectile motion, what is the relation between initial angle and speed at a given distance [closed]

I am trying to understand the relation between the initial angle of a projectile and its initial speed, given that the distance this projectile will travel is fixed and at the same height as the ...
2
votes
0answers
134 views

Air resistance of a general shape object

I'm trying to code a simple physics simulator in C++ but I'm stuck on the air resistance issue. Surfing the Internet I only find a drag coefficient for very basical area shapes when the air is ...
2
votes
1answer
221 views

Vertical circular motion followed by projectile motion

If you have a stone tied to a string, and it is given a certain velocity at the lower most point such that it completes a quarter circle but then the string becomes slack, and it undergoes projectile ...
2
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5answers
167 views

How does this shell hit the aircraft?

A fighter aircraft is flying horizontally at an altitude of 1500m with speed of 200m/s. The aircraft passes directly overhead an anti-aircraft gun. The muzzle speed of the gun is 600m/s. ...
-2
votes
1answer
90 views

Rigid Body Mechanics In a vacuum (no gravity) [closed]

I am writing a physics engine to map the rotary and translatory movements of a uniformly dense solid cylinder within 3d space. If a vectored thrust is applied to one end of the cylinder at an ...
1
vote
2answers
112 views

Measuring the velocity of a pendulum using the width of the bob

I did an experiment on pendulum motion and in the method it says use the following equation to measure the velocity of the pendulum: $$v=\frac{W}{t}$$ where $W$ is the width of the pendulum bob and t ...
1
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1answer
612 views

Is squared motor gearbox ratio proportional to inertia ratio?

I read an interesting article http://m.machinedesign.com/news/motor-sizing-made-easy It is very interesting, but I can not follow the 2nd last paragraph. I don't understand why it is true. ...
0
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1answer
112 views

Find shadow's height

Just starting to learn physics. Now reading about constant motion and after this paragraph I have a task: Boy with growth of 1.5 m runs at a speed of 3 m / s in a straight line, passing under a ...
1
vote
2answers
153 views

Steering forces on a bicycle

Ok, I always notice this weird thing and try to overcome it but cant. Ok as shown in the image when I ride the bike by just one hand and pull the handle back say from the right side so as commonly the ...
0
votes
3answers
3k views

How can an object with zero acceleration move?

My physics text has a problem in which it is said that a person moves a block of wood in such a way so that the block moves at a constant velocity. The block, therefore, is in dynamic equilibrium and ...
3
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3answers
343 views

Physical Variables of Circular Motion

To me, the definitions of variables involved in circular motion are rather confusing (perhaps due to the lack of understanding on my part), hence the question. As I understand it, there are two ...
0
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3answers
141 views

Interpreting the equation $\vec F = R\vec v$

The Aristotle's law of motion, which is incorrect, states that The velocity of an object $\vec v$ is directly proportional to the force $\vec F$ acting on it or $\vec F \propto \vec v$ ...
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vote
2answers
174 views

Why can't some light ever reach earth? [duplicate]

Note: I'm a layman in physics. Excuse me if this question is a duplicate, I lack the knowledge in technical terms to find the answer to this by research (I've tried). Let's suppose there's a star ...
-2
votes
1answer
108 views

Simple pendulum and planet mass [closed]

A simple pendulum, $20cm$ in length, has the period of $2.7s$ on a certain planet. Find the mass of the planet if its diameter is $18000km$. $G=6.67\times10^{-11}Nm^2/kg^2 $ I have no idea how to get ...
3
votes
2answers
264 views

Newton's First Law of Motion; Empirical Aspects

Newton's first law states that in an inertial frame, a body at rest continues to be at rest, and a body in constant rectilinear motion continues its motion, unless an external force is applied upon ...
1
vote
0answers
49 views

Books describing motion of objects in fluid [closed]

I'm looking for any resources that would help me model the behavior of objects moving in fluid. My end goal is to be able to describe the motion of irregularly shaped objects in a river environment. ...
-1
votes
1answer
226 views

Acceleration, velocity and speed

It is given that acceleration is constant, so can we infer that average speed and velocity are the same?? Moreover, circular motion is out of the question, as the function of x(t) where ...
4
votes
3answers
292 views

Does more rain strike a vehicle while moving or while stopped (or neither)? [duplicate]

Assume there is a rainstorm, and the rain falling over the entire subject area is perfectly, uniformly distributed. Now assume there are two identical cars in this area. One is standing still, and ...
1
vote
1answer
276 views

Convert a 200mm linear stroke into 90 degrees motion [closed]

Can anyone help me Convert a 200 mm linear stroke into 90 degrees motion with as much mechanical advantage as possible or into two 90 degrees motions with as much mechanical advantage as possible? ...
1
vote
1answer
174 views

Fundamental properties of motion

The first paragraph of the Wikipedia article on the angular momentum operator states that In both classical and quantum mechanical systems, angular momentum (together with linear momentum and ...
3
votes
1answer
158 views

Calculating the path of a ball with spin moving across a table

A ping pong ball is rolling over a smooth (but not frictionless) table. During its travel, a clockwise spin is placed on the ball. The ball's path is changed to move to the right (in perspective from ...
4
votes
3answers
165 views

If an electric car were to drive without having to stop, would the range be greatly affected by the speed at which the vehicle is moving?

Of course aerodynamics factors into this question, and the faster you are moving the more air you have to push out of your way, the more energy you use. But would the difference be only a small ...
-2
votes
1answer
315 views

Newton first law of motion, braking suddenly in car

While driving down the road, if you hit the brakes suddenly, your body moves forward. Explain the reason for this.
1
vote
3answers
373 views

Projectile motion, canon vs cliff

A cannon is placed at the bottom of a cliff 85 m high. If the cannon is fired straight upward, the cannonball just the reaches the top of the cliff. a) Calculate the initial speed of the cannonball. ...
2
votes
2answers
165 views

London into Australia in 90 minutes

Me and my friend are having a debate on whether it would be possible for a human to travel at 15,000 miles an hour from London to Australia in the matter of 90 minutes. Would a human be able to ...
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2answers
410 views

What is a natural movement of a ball on a upward curve (the two arrow lines pointing upward) given no external force?

If you drop a ball down a upward curving parabolic ramp, what is the expected movement of the ball? Assume the ball is set into motion with no external force. Would it go all the way from point A to ...