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.

learn more… | top users | synonyms (3)

0
votes
1answer
20 views

On the connection between forces and the principle of stationary action

Feynman tries to account for the relation between the principle of stationary action, which is a statement about the whole path of a particle, and Newton's second law, which is a statement about the ...
-1
votes
0answers
39 views

Intro Mechanics: Finding ball speeds after collision

So I'm reading about conservation of energy, momentum, balls colliding etc. and unsurprisingly there are hundreds of questions in my textbook where essentially they give me some of the variables (m1, ...
0
votes
1answer
25 views

Slingshot Energy into traveled distance [on hold]

If I have a slingshot and I am told that when pulled it has about $E$ joules of energy, how do I compute the height at which an object of mass $m$ would travel if the slingshot is released in the ...
2
votes
2answers
30 views

Is sonic boom louder than the sounds that a object traveling at the speed of sound makes, if so why?

Here are the wave-front models for both: I am in an introductory physics course. Just learned about this. I am not entirely sure if sonic boom is louder. But from what I saw, it's loudness is ...
-1
votes
0answers
37 views

Proof of Poisson equation in a gravitational field [on hold]

Can anybody show me how to prove Poisson's equation in Newtonian Gravitational field?
-1
votes
3answers
39 views

What is extension produced in spring? [on hold]

Consider a spring -block system given in the figure : Note: K is spring Constant. Initially, the spring was unloaded. After that, a block of mass M is loaded to spring and as a result, the spring ...
-4
votes
0answers
29 views

Point of getting each other after chasing! [on hold]

Imagine that 3 particles are on the angles of equilateral triangle with the $a$ side and they are chasing each other with velocity of $v_0$ . 1- What is the covered distance when the get each ...
17
votes
6answers
2k views

Conical train wheels

I've been reading about how the conical shape of train wheels helps trains round turns without a differential. For those who are unfamiliar with the idea, the conical shape allows the wheels to shift ...
5
votes
3answers
254 views

Is it true that spring has more force acting on it at its positive maximum amplitude than than at the negative one?

Am I missing something? It seems obvious to me that at $+A$ and $-A$, the spring has restorative forces equal in magnitude but opposite in direction. But since gravity is always pulling it down, ...
1
vote
1answer
62 views

When we ride a bicycle, why do we tend to move left when we turn it right? [duplicate]

When we ride a bicycle, we tend to move our body left if we are taking a right turn and vice versa. Why is it like that?
-2
votes
2answers
60 views

Why do cylinders roll easily and not square or rectangular slabs? [duplicate]

Why do cylinders roll easily and not square or rectangular slabs?? Let us say both have same materiel and vertical dimensions? What is the reason for the slab always tends to slide?
1
vote
0answers
42 views

Showing that a mass moves a half cycle

Consider a mass $m$ at position $x(t)$ on a rough horizontal table attached to the origin by a spring with constant $k$ (restoring force $-kx$) and with a dry friction force $f$ $$\begin{cases} ...
1
vote
0answers
60 views

How to integrate this physics model? [on hold]

OK, this might seem easy... but I'm having trouble solving it. Let's say I have a force acting on a body whose mass is known, by this law: $$F(t) = bt^2$$ where $b$ is a known constant, and $t$ is ...
3
votes
1answer
60 views

What makes us twist in a somersault?

In a backwards straight somersault you can decide whether you twist early or late. Twisting early means, that you induce the twisting movement before you rotatation hits 180° and twisting late means, ...
-2
votes
2answers
47 views

Intitutive meaning the unit of Force $N$

I infer 1 Newton of force = 1 kg.m/ sec squared means a force if acting continuosly on a body at rest would make it gain an acceleration of 1 m/sec squared each second.So the change in velocity is 1-0 ...
-2
votes
0answers
22 views

Vertical throwing exercise [on hold]

I'm struggling with this question Assume an object is resting on the ground, in $t=0$ there is a force that starting to work on it, which grants him vertical acceleration towards up, $a=3m/s^2$, ...
-1
votes
0answers
22 views

A problem from the Rudolf Ortvay Competition in Physics [on hold]

PROBLEM STATEMENT: A uniform circular disc is kept face down on a table which has a uniform friction coefficient.It is pushed in such a way that there is translational as well as rotational motion of ...
0
votes
1answer
56 views

Can forces in N be thought of as a length? [on hold]

A solid uniform 45.0 kg ball of diameter 32.0 cm is supported against a vertical friction-less wall using a thin 30 cm wire of negligible mass. (a)make a free body diagram for the ball and use it to ...
0
votes
2answers
61 views

Why are force, momentum, and kinetic energy derivatives of each other [on hold]

Force $ma$ is the rate of change of momentum, or the derivative of momentum with respect to time $$\frac{d}{dt} mv = ma = F$$. Kinetic energy is the integral of momentum with respect to velocity: ...
4
votes
3answers
1k views

In general, why do smaller guns have more felt recoil?

Why is recoil easier to control on a more massive gun compared to a smaller gun with the same bullet. Presumably the bullet leaves both guns with the same momentum, but the larger gun seems easier to ...
1
vote
1answer
51 views

Can mass-less spring system be solved?

Suppose we have typical chain of strings with masses, attached to the walls (W) at each side W-----m-----m--------W x=0 x=6 x=12 x=21 So if we let ...
0
votes
2answers
45 views

When is work done on or by something?

An example, here what my textbook says: When charges are released In electric fields charges experience the force causing them to accelerate along electric field vectors. Positive charges ...
1
vote
0answers
23 views

Whether the horizontal momentum vanishes when a rope sliping from a desk?

I meet this question in Thornton and Marion's Classical Dynamics of Partical and Systems, 5th ed, chapter 7: An extremely limber rope of uniform mass density, mass $m$ and total length $b$ lies on ...
-5
votes
1answer
31 views

Question based on friction force [on hold]

How will you solve this question using high school physics? It is based on friction force (as you can see, obviously). I have problem determining the direction of friction.
-9
votes
1answer
50 views

Can you help me with physics homework please? [on hold]

An object with a mass M is suspended from an elastic spring with a spring constant k. The object oscillates with period T on the surface of Earth. If the oscillating system is moved to the ...
0
votes
3answers
51 views

Reaction Force on String Wrapped Around Circular Peg

A massless inextensible string is wrapped around a frictionless circular peg. The string is taut, with tension $T_2$ and $T_1$ at the points where it leaves of the pg as shown. The segment wrapped ...
-2
votes
0answers
24 views

Calculating deceleration time - help! [on hold]

I'm struggling with a question due to not having the correct formula, so I hope someone can help! A 10000kg object is travelling at 15m/s, and a force of 600N is applied in the opposite direction to ...
-1
votes
3answers
115 views

Isn't a physical frame of reference useless for calculating speed? [on hold]

Please ignore relativistic effects and the effects of the expansion of space-time due to the expanding universe theory for the purposes of this question. Whenever someone asks what is the speed of X, ...
0
votes
1answer
34 views

What is force of static and kinetic friction? [on hold]

While I am asking more than one question in this thread they are all small concept tests that you can answer with a yes or no, and is all related to me understanding kinetic and static friction. ...
1
vote
5answers
82 views

What happens to the kinetic energy of a dropped ball when it comes to rest on the ground?

If we want to drop a ball from a height, we calculated that potential energy at bottom is zero and we say it is converted into kinetic energy. At that movement, if it is a kind of sand, we find it ...
0
votes
0answers
56 views

Why is it harder to stand still than to walk? [on hold]

I can walk for miles, but I'm exhausted after an hour of standing. I think it is not psychological. Is there any explanation according to physics?
1
vote
2answers
62 views

Tension in a massless string as it bends around a concave shape

I understand that tension in a massless string must be the same throughout when the string is straight, to prevent any section of it from accelerating at an infinite rate. However, I fail to see how ...
0
votes
1answer
40 views

When will a ball running between two downwards slopes stop going back and forth?

Two angles $a$ and $b$ meet at a point, making an angle $c$ between them. $a$ and $b$ are all $0 < \theta < π/2$. $c$ is $π/2 < \theta < π$ $a$ is to the left and opens to the left, $b$ ...
0
votes
0answers
68 views

Finding the tension/acceleration of a pulley

I redid the entire thread with pictures. Please click the link to see a picture of pulley with it weights. You see the equation at the bottom of the picture. ...
0
votes
2answers
21 views

Degrees of freedom of a two particle rigid system

we have two particles and the distance between them is fixed, lets suppose we know the coordinates of one particle (2,1) and other particle (x,2). So using distance formula(lets suppose the fixed ...
-1
votes
0answers
15 views

independent characteristics of force [closed]

I would like to know whether there exists independent characteristics of force or not. I read somewhere that the force does not posses independent characteristics. Is it correct? Support your answer ...
-1
votes
0answers
36 views

My physics question is about dynamics of a particle [closed]

A body of mass $2$ kg is acted upon by two forces each of magnitude $1$ Newton, making an angle of $60^{\circ} \simeq 100^{\circ}$ with each other. The net acceleration of the body (in ...
2
votes
2answers
24 views

What happens to a radioactive element or isotope's electrons when it undergoes alpha decay? [duplicate]

It seems to make sense that when an atom loses two protons, it would lose two electrons as well, but I don't actually know what happens.
3
votes
1answer
128 views

How does the Pluto-Charon orbital 'dance' affect Pluto's elliptical orbit around the Sun?

Like many Scientists (and people in general), I have been watching the New Horizons mission results with great interest. One aspect in particular caught my attention - the Pluto-Charon orbital ...
-3
votes
2answers
57 views

Spring balance: what will be the reading? [duplicate]

There are two cases: When the two forces say L (for left) and R (for right) are equal. F=L=R What will be the reading? I know the reading would be F but why? When the two forces are unequal that ...
1
vote
3answers
58 views

A block sliding down a ramp lab (with friction), I keep getting a higher final energy than initial

A block of 55 g is sliding down a ramp of 35 degrees of inclination. The hypotenuse of the ramp is 63 cm and the height is 36 cm. vi = 0 as the block starts at rest. I did 3 trials of letting the ...
4
votes
1answer
54 views

Finding minimum time to raise a bucket

First of all, I wonder: in $F=ma$ does the acceleration have to be constant? I believe so but, just as confirmation. Problem: A 4.80 kg bucket of water is accelerated upward by a cord of ...
7
votes
6answers
1k views

Why is friction force negative in ice skater problem?

A 68.5 kg skater moving initially at 2.40m/s on rough horizontal ice comes to rest uniformly in 3.52s due to friction from the ice. What force does friction exert on the skater? I am not really ...
0
votes
2answers
86 views

how is this kind of rolling motion possible?

I was solving this problem : Suppose you put a sphere in a rough ground with velocity of center of mass $v_{cm}= v_o$ in the positive $x$ axis and with anticlockwise angular momentum $\omega_o$ so ...
-3
votes
0answers
15 views

Work-energy theorem? [duplicate]

The initial kinetic energy of an object moving on a horizontal surface is K.Friction between the object and the surface causes the velocity of the object to decrease uniformly to zero in time,t.How ...
-1
votes
0answers
9 views

Work energy theorem problems [duplicate]

The initial kinetic energy of an object moving on a horizontal surface is K.Friction between the object and the surface causes the velocity of the object to decrease uniformly to zero in time,t.How do ...
-1
votes
0answers
36 views

Solving kinetic energy without numbers [closed]

The initial kinetic energy of an object moving on a horizontal surface is K.Friction between the object and the surface causes the velocity of the object to decrease uniformly to zero in time,t.How ...
0
votes
2answers
29 views

What is the work done?

A painter uses 1.93kJ of mechanical energy to pull on the rope and lift a 20kg paint barrel at constant speed to a height of 7.5m above the ground. How much work was done lifting the paint barrel? ...
0
votes
2answers
76 views

How to solve this pendulum problem using kinematics, not the principles of conservation of energy?

I have this question, because typically problems that can be solve using conservation of energy or just energy-related principles, can usually be solved sing kinematic equations. (At least is what I ...
1
vote
3answers
41 views

Is work-kinetic energy theorem useless?

This is how my book explains it: $W_{net} = \delta K$ Since the net work is tied to changes in kinetic energy and changes in speed, a mass must accelerate in order for net work to be nonzero. ...