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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Newton's second law of motion in terms of momentum
I am reading a document and in answer to the question State Newton’s second law of motion the candidate answers that The force acting on an object equals the rate of change of momentum of the object. ...
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1answer
158 views
Deceleration of Vehicle off pavement
How would I calculate the deceleration of a vehicle (ATV), wheels locked, on dirt? How long would it take to halt? How fast is it decelerating?
I used this calculator, but it seems incorrect for a ...
2
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1answer
62 views
Convert a 200mm linear stroke into 90 degrees motion
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?
...
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3answers
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Why does a rod rotate?
I'm a physics tutor tutoring High School students. A question confused me a lot.
Question is:
Suppose a mass less rod length $l$ has a particle of mass $m$ attached at its end and the rod is ...
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3answers
261 views
A man running on the treadmill
Imagine a man is running on a treadmill. His inertia with respect to floor will be zero because he is not moving with respect to floor. If both he and the tread mill suddenly stops he will not fall, ...
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1answer
111 views
Opposing forces on an air cylinder
If an air cylinder is pushing two platens apart with a force of 100lbs, do the platens need to push back at 100lbs or 50lbs each to keep the cylinder from moving? Assume no friction and both platens ...
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Is there any true inertial reference frame in the universe?
Is there any true inertial reference frame in the universe?
Newton's first law states that an object at rest remains at rest, and an object performing uniform motion performs uniform motion, until ...
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0answers
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Mechanics: collision & rotation [closed]
A rod AB of mass M and length L is lying on a horizontal friction less surface. A particle of mass m traveling along the surface hits end A of the rod with a velocity 'v' in a direction perpendicular ...
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1answer
251 views
Is acceleration an average?
Background
I'm new to physics and math. I stopped studying both of them in high-school, and I wish I hadn't. I'm pursuing study in both topics for personal interest. Today, I'm learning about ...
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0answers
36 views
Compound pendulum clarification?
I read in a book the following about compound pendulum and small displacements:
There are two points only for which the time period is minimum.
there are maximum 4 points for which the time ...
0
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0answers
15 views
Collision response between a mass and a line attached to two masses [closed]
I'm currently in the making of a small simulation program and, as I am very new to physics, I am struggling with what seems to be a simple 2D collision response problem.
I spent quite some time ...
3
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7answers
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Simple friction formula for a car
I am making a 2D driving video game, and I would like to know the "simple" formula for calculating the friction force between the car and the road. I have read lots of friction diagrams involving ...
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2answers
143 views
Semi-major axis and ellipticity of a binary system?
In the image below (source at bottom), it seems to be suggesting that
\begin{equation}
a = a_{1} + a_{2}, \hspace{8cm}(1)
\end{equation}
where $a_{1}$ and $a_{2}$ are the semi-major axis of the ...
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0answers
50 views
Frequency with the spring scale [closed]
Grocery stores often have spring scales in their produce department to weigh fruits and vegetables.
The pan of one particular scale has a mass of $0.5 kg$, and when you place a $0.5 kg$ sack of ...
0
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0answers
36 views
How can I find the frequency? [duplicate]
Grocery stores often have spring scales in their produce department to weigh fruits and vegetables.
The pan of one particular scale has a mass of 0.5 kg, and when you place a 0.5 kg sack of potatoes ...
0
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3answers
652 views
Who is right? Force exerted on a body. Me or my friend?
Three masses $m_1 = 3\text{ kg}$, $m_2 = 9\text{ kg}$ and $m_3 = 6\text{ kg}$ hang from three identical springs in a motionless elevator. The elevator is moving downward with a velocity of $v = ...
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2answers
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Equations for an object moving linearly but with air resistance taken into account?
I know (from Kinematics) that for an object moving linearly with an acceleration and without air resistance the following equations can be used to determine v(velocity) or x(position of the object) at ...
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1answer
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How did Newton find out force has something to do with acceleration?
Its about Newton's second law of motion,
$$F=ma.$$
It says the acceleration of an object is directly proportional to the net force and is inversely proportional to the object's mass. Yes I can ...
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3answers
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Mass equals Moment of inertia when constant density?
I have found equation for moment of inertia $(J)$. I'm calculating $J$ for hemisphere, with rotational axis $Z$.
$$ J = \iiint\limits_V r^2 \cdot \rho \cdot dV $$
But if $\rho$ is constant ...
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0answers
32 views
Baseball rolls off desk [closed]
An autographed baseball rolls off of a 1.0 m
high desk and strikes the floor 0.67 m away
from the desk.
How fast was it rolling on the desk before
it fell off? The acceleration of gravity is
9.81 m/s2.
...
2
votes
3answers
135 views
Is Newtonian gravity consistent with an infinite universe? [duplicate]
Let us assume that we have have an infinite Newtonian space-time and the universe is uniformly filled with matter of constant density (no fluctuations whatsoever), all of it at rest. By symmetry, the ...
0
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1answer
102 views
Earth's rotation isn't that orbit?
If the earth is rotating at some $465~\text{m}/\text{s}$ at the equator and that's really fast.
Shouldn't we in that case be in orbit with the earth just not fast enough?
How fast do we need to ...
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2answers
69 views
What's the motion of this yoyo under external force will be?
A yoyo on a horizontal table is being pulled by a string to the right, the table is not frictionless. If we only know that the object doesn't slip, how do we know if the string is winding up or ...
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0answers
44 views
Dynamics of an object hitting a spring [closed]
In a one dimensional universe, there is an object of mass m, heading towards a spring (which is attached to a wall of infinite mass) of spring constant k, at a constant speed of u (i.e. acceleration ...
3
votes
1answer
75 views
How do I calculate how something should stay in position under gravity?
Excuse me if this too simple a question - I'm not a regular (consciously) user of physics.
I have a ship in space and it is under the effect of three moons. The ship can rotate and thrust to move ...
2
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0answers
91 views
Why did increasing the Ackermann geometry in my race car make it faster in corners?
Ackermann geometry is used to account for the different radius arcs that the front tires follow when the steering wheel is turned from center. It's often expressed as a percentage: e.g. 25% Ackermann, ...
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3answers
91 views
Parachute in vacuum
Consider that the earth is vacuum. Consider a person of weight 100 kg is falling from sky with an parachute . He is free falling at height of 3000 m. When will he reach the ground? What would happen ...
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12answers
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List of good classical physics books
What are some good books for learning the concepts of Kinematics, Newton laws, 2D Motion of Object etc.?
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2answers
115 views
If the moon was rapid enough would it be able to orbit the earth from a close distance?
If the moon was close in orbit that it's surface was like 100 km away from the earth's surface. And it had a large enough angular velocity will it be able to hold orbit?
If this was possible, is ...
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1answer
31 views
Find the bending moment of a pole attached to a moving block
I'm having trouble with the following problem.
What I've done so far:
x-y is the usual coordinate system.
$a=\frac{F}{m}=\frac{800}{60}$ and the y component of this is $a_y=a\sin{60^\circ}$.
To ...
15
votes
5answers
273 views
Does the mass point move?
There is a question regarding basic physical understanding. Assume you have a mass point (or just a ball if you like) that is constrained on a line. You know that at $t=0$ its position is $0$, i.e., ...
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3answers
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What needs to be integrated to solve this problem?
An object is placed on a frictionless table with its one end attached to a cord which is connected to a pulley and the tension is maintained constant at 25 N. what is the change in kinetic energy ...
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2answers
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Whats the anti-torque mechanism in horizontal take-off aircraft?
In most helicopters there is the anti-torque tail rotor to prevent the body from spinning in the opposite direction to the main rotor.
What's the equivalent mechanism in horizontal takeoff single ...
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3answers
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Why are Saturn's rings so thin?
Take a look at this picture (from APOD http://apod.nasa.gov/apod/ap110308.html):
I presume that rocks within rings smash each other. Below the picture there is a note which says that Saturn's rings ...
25
votes
6answers
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Can I survive a free fall using a ramp and a rope?
Can I survive a free fall by carrying a very light and resistant ramp using a rope?
Note: lets assume the ramp is a little bit heavier at the bottom and I am very skilled at making it always land ...
0
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1answer
79 views
Kinematics with non constant acceleration
A particle experiences an acceleration described by
$$
a=kx^{-2}
$$
where x is the displacement from the origin and k is an arbitrary constant.
To what value does the velocity v of the particle ...
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1answer
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Hollow stone columns provide more support?
In history class in elementary school I remember learning that the Greeks would build their stone columns hollow because they thought this provided more support. Is it true that a hollow column is ...
4
votes
1answer
258 views
Lagrangian dynamics with initial conditions: motion of free particle
I am very new to Lagrangian dynamics so I am trying to get my head around the practical usage. So far on here all I could find were proofs and they did not make much sense to me, especially when time ...
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1answer
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How do you find (initial) velocity using conservation of energy?
Without mass; only time, distance, and height is given. For example:
For this lab, the reference level was 100cm above ground therefore the height of the object was 10cm. I determined time and ...
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1answer
39 views
Finding the acceleration at an angle
"What's the maximum acceleration you can achieve in a a water-slide at a 34 degree angle (If you can't use your arms and legs)"?
This is the free-body-diagram that I drew, assuming $g = 10m/s^2$:
...
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votes
1answer
58 views
Direction of the torque
In each one of the following figures there's a pole of length $1.2
\text{m}$ and there's a force $\vec F = 150 \text{N}$ acting on it.
Determine the torque that is created by the force relative ...
1
vote
2answers
991 views
Why does a ball bounce?
If an object is acted on by equal and opposite forces then it will be in equilibrium, and it's acceleration or velocity (and so direction as well) will not be changed.
So when a ball bounces, it ...
2
votes
2answers
139 views
Conical Pendulum — Can it rotate at 90 degrees?
I have a simple question, can you spin a conical pendulum fast enough so that it rotates at 90 degrees?
The equation is $\tan(\theta)=v^2/rg$ , but at 90 degrees, $\tan(\theta)=\infty$ ... so what ...
3
votes
3answers
136 views
Non-SHM oscillatory motion
How to solve these kind of questions , where $|F| \propto x^2$?
How to find time period and velocity type related things to the oscillatory motion?
...
0
votes
5answers
172 views
Why is momentum conserved (or rather what makes an object carry on moving infinitely)?
I know this is an incredibly simple question, but I am trying to find a very simple explanation to this other than the simple logic that energy is conserved when two items impact and bounce off each ...
0
votes
1answer
63 views
What Speed Would an object need to leave the earth at to reach L1? [closed]
Let's say the Earth is an airless sphere. What speed would an object weighing 1 kg need to leave the surface at in order to get to and be motionless at L1, where the Moon's gravity becomes stronger ...
1
vote
1answer
127 views
Cylinder rolling down an inclined plane held by a string
A cylinder of mass M and radius R is in static equilibrium as shown in the diagram. The cylinder
rests on an inclined plane making an angle with the horizontal and is held by a horizontal string
...
5
votes
2answers
239 views
Explanation that air drag is proportional to speed or square speed?
A falling object with no initial velocity with mass $m$ is influenced by a gravitational force $g$ and the drag (air resistance) which is proportional to the object's speed. By Newton´s laws this can ...
2
votes
2answers
109 views
Elastic collision and spring
Bodies $A$ and $B$ are moving in the same direction in a straight line with a constant velocities on a frictionless surface. The mass and the velocity of $A$ are $2 \text{kg}$ and $10 \text{m/s}$. ...
0
votes
1answer
72 views
Newton's second law?
$F=ma$. A car strikes a wall at 60 mph. Its acceleration is zero at the time. The force of the car against the wall or vice versa is? To look at the car the force is not zero. Please explain.
