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
3answers
43 views

2 airplanes same size and shap different mass

2 identical balls of different mass dropped from same height reach the ground at the same time due to the acceleration of gravity being constant. If I understand correctly the ball with more mass ...
4
votes
2answers
1k views

How do I experience Earth's movement?

We are told that Earth is spinning on its axis at 1037 mph— something that we don't usually feel because of the environment that moves with us as well. Is there any experiment with which we can know ...
0
votes
2answers
47 views

What is relationship between linear and angular momentum?

I'm confused about imparting momentum to a sphere, which causes it to rotate without slipping. Does the momentum applied go: only to the rotational motion and the linear is a consequence of the ...
1
vote
4answers
46 views

how is a pendulum clock's time and the time period of the pendulum in it related? [closed]

I'm working out how much time a pendulum clock will gain or loose due to change of the length of the pendulum due to temperature. so far I've got, new time period, $$T_2=T_1(1+\frac12\alpha\Delta T)$$ ...
2
votes
2answers
114 views

Fired a bullet upwards, can it fall down and kill me?

I know that if something is thrown up with a velocity v, it comes down with the same velocity as long as its motion faces no resistance. So is it possible for me to fire a bullet and be killed if it ...
1
vote
1answer
49 views

What makes cart with a moving object in it gain speed (no friction anywhere)?

I would like to understand what makes the cart below the moving object move. There is no friction between any of the objects. The cart is moving therefore there is force applied to it. The only force ...
2
votes
2answers
54 views

Why dont you take derivative of force in definition of power ? P=F.v

The derivative of work is $\bf F\cdot v .$ $$P(t)= \frac{\mathrm dW}{\mathrm dt}= \mathbf{F\cdot v}=-\frac{\mathrm dU}{\mathrm dt}\;.$$ But why not $$(\mathrm d(\mathbf F)/\mathrm dx)\cdot \mathbf x ...
0
votes
2answers
43 views

Work-Energy Problem

A wire, which passes through the hole in a small bead, is bent in the form of quarter of a circle. The wire is fixed vertically on ground as shown in the figure. The bead is released from near the top ...
3
votes
0answers
28 views

The physics of an anvil [closed]

I am trying to understand how an anvil might best be made. An anvil requires two essential characteristics: enough hardness to not be deformed under the blows of the hammer, but as little rebound and ...
1
vote
0answers
40 views

What is the path taken by a “cable car”?

A well known result in variational calculus & Lagrangian Mechanics is the solution to the "brachistochrone" problem, where it is found the path connecting two points, A & B such that the time ...
0
votes
1answer
24 views

Massless rope in a pulley pulled by a person

A massless rope passes through a pulley. On each end of the pulley there is a different mass (object). A person grips one of the masses and thus the system comes to equilibrium. How would you ...
-1
votes
2answers
90 views

Conservation of momentum and conservation of energy

I had the impression that conservation of momentum is valid only when we consider no loss of kinetic energy into heat etc. My tutor says that even if we have loss of kinetic energy as heat in a ...
5
votes
4answers
289 views

What will be final velocity of three charges $q$, $q$, $2q$? [on hold]

What will be final velocity of three charges q, q and 2q kept along an eqilateral triangle of side r at infinite distance. All three masses are equal. I tried to conserve Total Energy ...
-1
votes
1answer
37 views

a problem on circular motion [closed]

Question:A cyclist is riding with a speed of $7.5$ m/s. As he approaches a circular turn on the road of radius $80m$, he applies brakes and reduces his speed at the constant rate of $0.50$ m/s every ...
0
votes
3answers
43 views

Direction of velocity and acceleration for a pendulum [duplicate]

The image below shows the direction between acceleration and velocity change with time. But it seems to me that the direction is not opposite. Can you please see and tell if this is correct?
0
votes
2answers
37 views

Objects and forces: air resistance

A force always works between two objects. When we are talking about air resistance acting on a skydiver for example, would air be considered the second objects besides the skydiver?
0
votes
3answers
48 views

Conditions for the tension to vary in the rope

What are the conditions for the tension to vary in the rope. I have read below conditions 1. rope has to have some mass 2. rope is accelerating I get the 1st ...
1
vote
2answers
31 views

Tension in the string

In the following diagram, what's the force that's acting on m, the Tension in the string? There is no friction between M and the ground but there is between m and M and I need to find the minimum ...
0
votes
3answers
83 views

What is the difference between these two springs?

I know that the stifness of the following springs are different. But how to find their spring constant? I think that one has the tension force is fully transmitted along the solid (but is it ...
1
vote
1answer
64 views

Does this count as a proper derivation of the formula for work and kinetic energy? [closed]

$v_{av}$ = average velocity, $d$= distance, $a$ = acceleration, $m$ = mass Given: $$v_{av}*t=d$$ $$t=\frac{v_f-v_i}{a}$$ $$v_{av}=\frac{v_f+v_i}{2}$$ Then: $$\frac{v_f+v_i}{2}*\frac{v_f-v_i}{a}=d$$ ...
1
vote
0answers
54 views

Eigenfrequencies of a truss

I want to calculate the eigenfrequencies of a 3D truss using the finite element method. The beams should be modelled as Timoshenko beams and I want to use arbitrary shape functions. I know how ...
0
votes
3answers
34 views

Effect of internal force on the weight of an object

A man is holding a closed cage on the palm of his hand with a bird in it. When the bird flies with an upward acceleration inside the cage, it feels heavier. But the force due to the bird in the cage ...
-2
votes
1answer
72 views

Boeing 737 Homework Problem [closed]

I have done the above problem, but have come out with a rather large surface area. Could someone point out my mistake(s)? Given/Assumptions: I assume $\sum F_y=0$ because it's level and straight. ...
1
vote
0answers
23 views

What forces act on a caravan being towed by a car? [closed]

What forces act on a caravan that is being towed by a car? How does this compare to a simple car travelling at a constant speed?
0
votes
1answer
47 views

Relationship $v_A^2-v_B^2=2a_t\Delta s $ for motion with constant tangential acceleration [closed]

I can not understand a relationship in the general motion in the plane. I am considering a point, which follows a curved trajectory. Indicate A and B two different position of the trajectory and $v_A$ ...
3
votes
1answer
45 views

Particle sliding down frictionless hemisphere on frictionless surface

http://web.physics.harvard.edu/uploads/files/undergrad/probweek/prob87.pdf http://web.physics.harvard.edu/uploads/files/undergrad/probweek/sol87.pdf The problem and the suggested solution are in the ...
1
vote
0answers
128 views

To prove uniqueness of the rotation tensor associated with rotation of a rigid body

Suppose there are $N$ particles embedded in a rigid body which undergoes some random rotation such that: $$ \overline{\overline {R}}_{ij} \otimes \vec{a}_{ij} = \vec{b}_{ij}$$ where, $i$ and ...
1
vote
2answers
45 views

Tension in string of two pulleys suspending two masses

There is a system composed a rope connecting two identical masses, each of mass $m$, suspended by two fixed pulleys. The system is in a static equilibrium. In between the pulleys, there is a tension ...
1
vote
0answers
23 views

Minimum energy transfer orbit for n-body system

Is it possible, in principle, to calculate a minimum energy transfer orbit between any two bodies in an n-body system? Even if one specifies a maximum elapsed time? My intuition is that, except in ...
0
votes
2answers
34 views

Magnitude of Tension: Circular Motion [closed]

Please consider the following: A tennis ball connected to a string is spun around in a vertical, circular path at a uniform speed. The ball has a mass m = 0.165 kg and moves at v = 4.76 m/s. The ...
1
vote
2answers
35 views

Static Equilibrium [closed]

A 3 Newton force and a 4 Newton force are acting concurrently on a point. Which force could not produce equilibrium with these two forces? 1N 7N 9N 4N I'm confused. The book I'm looking at says ...
1
vote
1answer
39 views

Calculating post-collision velocity [closed]

Consider two persons $p1$ and $p2$ of the same mass , such that they are together moving rightward with a velocity of $v/2$ Now person $p1$ pushes $p2$ in the left direction. According to newton's ...
1
vote
2answers
48 views

When a ball bounces on a wall at an angle, why does the angle of incidence equal angle of reflection?

When a ball is thrown to a wall without spin and bounces, supposing it's an elastic collision, why does the angle of incidence equal the angle "reflection" (relatively to the normal), why isn't it any ...
0
votes
0answers
22 views

$16~\rm N/mm^2$ flexural strength

This question more relates to construction and architecture but I am sure it will not be the problem to ask and get a good answer here. If we have declared flexural strength of concrete of 16 N/mm2, ...
0
votes
1answer
29 views

The equation for average impact force over distance traveled/penetrated equals work done/change in kinetic energy [closed]

So the equation Favg * d = Work or change in kinetic energy, is this true? If a car crashes into a tree by 1 meter with 10000 joules, is the impact force on the car 10000 Newtons? If a bullet ...
1
vote
0answers
13 views

wind force necessary to move large garbage bag on ground--snow covered and grass [closed]

I am wondering what handy reference figure in mph in the wind (with and without gusts) is prudent in whether to put put a 30 gallon plastic bag of standard garbage or not?? I live alone and often only ...
1
vote
0answers
63 views

Simple powertrain dynamics

I'm trying to simulate vehicle powertrain and having problems at calculating correct impulse at the wheel. Here's what I have. Gear Ratio There are two gear ratio in the system $N_g$: ...
0
votes
1answer
20 views

Why, here, the torque with respect to bob is zero?

here, as you see, is a diagram of a pendulum with moving pivot along x-y surface. This picture was obtained from a journal in which this equation was written: $$F_x l \cos\theta = F_y l \sin\theta ...
1
vote
0answers
51 views

What happens when one uses a blender in zero gravity?

I was recently told by a friend that using a blender type apparatus in a zero gravity environment will act like a centrifuge instead mixing properly. Is this the case? Furthermore, can anyone provide ...
0
votes
1answer
41 views

Why the force acting on a particle is the negative gradient of a scalar potential? [closed]

For conservative forces we can proof that it is a gradient of a scalar potential, but why we use the negative sign? In every book I searched, it said that it is like an agreement between physicists, ...
0
votes
0answers
7 views

Understanding the inertia matrix of a tilted ellipse

I would like to control the rotation of an ellipse which is tilted by 45° with respect to the rotation axis, and I need to calculate the inertia of the load on the shaft. To be clear, on this figure I ...
3
votes
1answer
61 views

Projectiles on inclined planes with coefficient of restitution [closed]

This is the problem I am currently attempting. So far, I've resolved the velocity parallel and perpendicular to the plane to get, perpendicular: $u \sin \theta$ upon launch and $-u\sin \theta$ on ...
1
vote
1answer
22 views

What causes the skidding of the wheels of a moving car? Momentum or inertia?

In a moving car, when brakes are applied suddenly the wheels skid.I have these two explanations in my mind and both seems correct to me.1. The momentum of the car must be conserved so the car ...
1
vote
4answers
108 views

Physics newb: Why can't I plug $E=mc^{2}$ into $W=mg$?

Starting with $E=mc^{2}$, I solved for $m$ and plugged the result into $W=mg$. Which was very confusing, as objects at rest had no weight: $$W = (e/c²)\cdot g \implies W = (0/c²)\cdot g \implies W ...
3
votes
0answers
19 views

How to efficiently cool down simulated gas by time-dependent potential?

I'm trying to simulate condensation of a highly diluted gas (a model gas, not any real one). For simplicity I restrict the simulation to 2 dimensions. To setup the simulation I take some interparticle ...
0
votes
1answer
69 views

Acceleration in a non-inertial reference frame

I have a conceptual doubt on the relation about the acceleration in a non inertial system. To explain the doubt without misunderstanding, I'm going to write the text of an exercise: A platform ...
1
vote
1answer
43 views

Couple of questions about Gravitational field of an infinite plane

Is it possible to find the gravitationaal field without using infinite integrals or Gauss's law? I would like to know if so because I haven't learnt doing infinite integrals or using Gauss's law yet. ...
1
vote
0answers
30 views

Does energy transmission depend on the speed of incoming particle?

Since a few past days , I am struggling with finding an in depth atomic model of force exchange between colliding paricles (originally newtons third law) , because at this point of time i am unable to ...
1
vote
0answers
25 views

Is there a way to find the optimal angle to launch an object to get maximum distance when there is an initial height? (Projectile motion) [duplicate]

I know that the optimal angle to launch an object at ground level is 45 degrees; however, i want to know that if there is anyway to get the optimal angle to launch an object to get the maximum ...
1
vote
1answer
51 views

Generation of artificial gravity by rotation

I have been trying hard to understand how Artificial Gravity is produced by Rotating a satellite around its own axis. Thus far, I have understood (probably wrong) that as a satellite is spun, walls ...