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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Two people pushing off each other
If there are two people on ice skates named A and B, and A pushes on ...
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1answer
461 views
Determine acceleration from experiment (Newton 2nd Law)
I have done a physics experiment (setup below). And was asked to determine the experimental and theoretical acceleration.
The data I've got
Ok, am I right to say
Experimental acceleration ...
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2answers
288 views
Why didn't Newton just propose the 2nd Law and leave it at that?
Why didn't Newton just propose the 2nd Law ($F=\dot{p}$) and leave it at that? The 2nd Law implicitly contains the first, doesn't it? If so, it seems he wasn't following his own Rule #1 of Book 3 of ...
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2answers
202 views
What sustains a rigid body's rotation at its constant angular(rotational) speed?
Continuing from the following scenario from my previous question Centripetal force of a rotating rigid body? :
Consider someone pushing a roundabout in a playground. Initially the
roundabout is ...
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3answers
251 views
Train crash: are these situations alike?
I was just wondering... I believe that if a car travelling 50 miles per hour crashes into a wall, the result should be the same as crashing to another car also travelling 50 miles per hour (but in the ...
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3answers
954 views
Why did they add a Centripetal Force in the Free-Body Diagram?
problem
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solution
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Why do they have the centripetal force in there? I understand that the normal force is the centripetal force here, but why would they say "or $\frac{mv^2}{r}$"? I thought it ...
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2answers
50 views
Clarification regarding Newton's Third Law of Motion and why movement is possible [duplicate]
Newton's third law states that to every action, there is an equal and opposite reaction.
If that's the case, then how do things move at all? Shouldn't all applied forces be canceled by the equal and ...
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1answer
77 views
Gravitational potential energy of mass between two planets
Suppose I want to launch a rocket from earth to some point $O$ between the center of earth and the center of moon (on a straight line connecting their centers), where the gravitational force of the ...
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4answers
145 views
How to get the angle needed for a projectile to pass through a given point for trajectory plotting
I am trying to find the angle needed for a projectile to pass-through a given point.
Here is what I do know:
Starting Point $(x_0,y_0)$
Velocity
Pass-through point $(x_1, y_1)$
I also need to ...
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3answers
564 views
What determines the direction of precession of a gyroscope?
I understand how torque mathematically causes a change to the direction of angular momentum, thus precessing the gyroscope.
However, the direction, either clockwise or counterclockwise, of this ...
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3answers
130 views
Displacement with zero velocity
I know that we can rotate a deformable object using internal forces only in space. Thus we can cause an angular displacement without the use of any external forces.
The following youtube video shows ...
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1answer
543 views
Newton 2nd Law: Does vertical force (mass) affect the horizontal acceleration?
I learnt before that if 2 forces are perpendicular to each other, they should not affect each other. However in a recent experiment setup (asked in another question):
I believe the theoratical ...
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1answer
342 views
What causes a force field to be “nonconservative?”
A conservative force field is one in which all that matters is that a particle goes from point A to point B. The time (or otherwise) path involved makes no difference.
Most force fields in physics ...
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1answer
96 views
Gravitation and equilibrium (…and similar problems)
One problem that I'm having trouble with (as opposed to the other):
The Messenger is a probe that orbits Mercury $700 \rm km$ from the surface. What is the tangential velocity it should be ...
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3answers
642 views
Centripetal force of a rotating rigid body?
Consider someone pushing a roundabout in a playground. Initially the
roundabout is stationary, but when it is pushed, it rotates with
increasing rotational speed.
The force of the push is ...
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1answer
469 views
Earth as approximate inertial frame of reference
In many practical applications one can consider the earth approximately as inertial reference system (though it is non inertial).
Is there any quotable reference, where this claim is supported by a ...
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1answer
217 views
Is this simulation following real physics?
I am trying to simulate a game in Box2D(Physics engine). The game that I am trying to simulate is very simple and can be found here: http://www.makaimedia.com/#/speartoss
What I want to know is that, ...
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1answer
56 views
Why body starts moving when force is applied? [duplicate]
The recent question by m.buettner regarding self-inductance and its resistance to EMF Faraday's law - does the induced current's magnetic field affect the change in flux?, recalled me 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 ...
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0answers
270 views
Non Harmonic Oscillator [closed]
Not every oscillation in nature is a harmonic oscillation - in this problem, we will examine a non-harmonic oscillation. Suppose we had a rubber ball with a perfect coefficient of restitution so ...
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1answer
139 views
What happens if object is thrown in empty space?
If I throw a object in empty space, I apply a force to throw that.
Then it gains some acceleration and it's speed increases.
So will it's speed keep on increasing, or it will get stable?
If yes, ...
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3answers
776 views
How to derive the period of spring pendulum?
So I wanted to find out how to (simply, if that's possible) derive the formula for a period of spring pendulum: $T=2\pi \sqrt{\frac{m}{k}}$. However, Google doesn't help me here as all I see is the ...
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1answer
89 views
Time of a ball going up and down with air resistance
A ball is shot directly upward, and then it comes back to the place where it was shot. Suppose we have air resistance. Suppose $t_1$ is the time period from the moment that the ball was shot to the ...
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0answers
258 views
Torque required to rotate a cement mixer..? [closed]
I need to design a motor to rotate a cement mixer which should mix one cubic meter. So, I calculated the required volume to be 1600 liters as it is an horizontal cylinder. Consider that the mixer ...
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2answers
719 views
Preventing a block from sliding on a frictionless inclined plane
I want to demonstrate what force $F$ you would have to exert on an inclined plane of angle $t$, mass $M$ to prevent a block on top of it with mass $m$ from sliding up or down the ramp. I worked out ...
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1answer
150 views
Condition for circular orbit
I am a little confused about the condition for circular orbit. Goldstein's Classical Mechanics has the condition for circular orbit as $$f^'=0\tag1$$ where $f^'$ is the effective force. I understand ...
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1answer
321 views
Pedestrian hit by small vs. big car
We have been discussing whether or not bigger cars are more dangerous to pedestrians. I will reduce it to a simpler question.
Imagine two cars, which are exactly identical in shape, but have ...
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2answers
338 views
Finding Distance an Object Travels Up an Incline After Launch
I've been doing a review for an introductory physics course final. I have a question on one problem though. Here is the problem:
A mass (M=2kg) is placed in front of a spring with k=900N/m,
...
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2answers
624 views
Two objects exert forces on each other, will the reactions affect them?
Two objects go in against each other, and then they collide, will object 1, exerting force 1, necessarily get on it a reaction equal in magnitude and opposite in direction?
EDIT:-
In my book it only ...
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2answers
1k views
What is the force exerted on a body that doesn't move?
If I push against a brick wall I'm exerting a force against the brick wall the the brick wall will exert the same force against me. These will cancel each other out and neither myself or the wall will ...
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0answers
57 views
What should my next step be after drawing a diagram? [closed]
I was training with some example exams, and I found out a problem that I don't know how to start with it, not even a main formula...
Two balls with masses of 0.5g each hang on threads 0.8m long ...
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3answers
2k views
Torque required to turn a drum/barrel
I need to spec a motor to turn a mixing barrel. The barrel contains loose earth and can be filled to a maximum of 50% of its interior volume. It is a horizontal cylinder, and will rotate through its ...
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3answers
375 views
Missing something basic about simple orbital mechanics
I seem to be missing something basic.
I've been trying to get a simple orbital simulation working, and my two objects are Earth around the Sun.
My problem is this. I placed the Earth at 93M miles ...
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1answer
47 views
Comparing Static Frictions
In this figure, which of the static frictional forces will be more?
My aim isn't to solve this particular problem but to learn how is static friction distributed . Since each of the rough-surfaces ...
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2answers
169 views
Stone thrown in empty space
This is a supplementary question to What happens if object is thrown in empty space?
Via the following logic:
$$E = \frac{(mv)v}{2}\\
E = \frac{pv}{2}\\
\Delta E = \Delta p\times \Delta ...
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2answers
109 views
A large rock falls on your toe. Which concept is most important in determining how much it hurts?
A) The mass of the rock
B) The weight of the rock
C) Both the mass and the weight are important.
D) Either the mass or the weight, as they are related by a single multiplicative constant, g.
...
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1answer
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A mechanics question of finding maximum K.E [closed]
The question is in the diagram as well the diagram
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2answers
614 views
Investigating damped Harmonic Motion in a Spring?
I'm going to conduct an investigation into the dampening of a spring.
Essentially, what specific factors could be investigated? Currently I'm planning to investigate the effect of changing the mass ...
