# newtonian mechanics

1. ### I What precisely is "Recoil"?

I am having some difficulty understanding what "recoil" really is with respect to momentum, force, and and time. On the one hand, momentum is considered to be the product of mass and velocity or perhaps the product of the sum of masses and some velocity, or some variant of P=mv, where P is a...
2. ### Classical Mechanics Problem Based On Conservation Of Energy

I have tried using Conservation of Energy but I'm getting incorrect answer.
3. ### I Physical model of the roulette wheel

Hello, I am having trouble understanding the two friction force terms from the ball rolling on page 4 of this physical model: http://www.dewtronics.com/tutorials/roulette/documents/Roulette_Physik.pdf What is the reason for the cos\theta term ? I think the frame of reference is made up of the...
4. ### A Conservation laws in Newtonian and Hamiltonian (symplectic) mechanics

In Newtonian mechanics, conservation laws of momemtum and angular momentum for an isolated system follow from Newton's laws plus the assumption that all forces are central. This picture tells nothing about symmetries. In contrast, in Hamiltonian mechanics, conservation laws are tightly...
5. ### Find the stretch of a steel wire in a static equilibrium problem.

If I can determine the weight of that heavy object placed on the plank, I will be able to determine the stretch of that wire. But, when using the second condition for static equilibrium (torques of the system equal to 0), I always end up with two unknowns, no matter what point of rotation I...
6. ### Solving this problem using the energy method

I attempted the solution using force method. I got correct. However, I was stuck at the alternative way to solve problem using energy method. As shown in screenshot 2, he tells that the energy of system changes due to 2 ways: - The tension T - Leaking of mass As shown in screenshot 2 ,the...
7. ### Boomerang Problem, need help solving it

1. Homework Statement A boomerang is thrown with an initial linear velocity of 5 m/s at an angle of 30 degrees vertically. The initial angular velocity is $2\frac{revolutions}{s}$ At its peak, it has a displacement about the z axis of 2 meters and about the x axis of 10 meters. The force...
8. ### A frictionless stick

1. Homework Statement This is the problem 8.62(in screenshot) from Morin's text book of Classical mechanics. I solved it using conservation of momentum in y direction. However in solution manual,he neglects the momentum in y direction by calling stick frictionless. What is this frictionless...
9. ### Atwood with cylinder

1. Homework Statement The problem is in attached screenshot. Now,I solved this using force/torque method. However ,I got different solution as given in solution manual. Where I have gone wrong? 2. Homework Equations 3. The Attempt at a Solution Applying F=ma to cylinder: $$mg-T=ma$$...
10. ### Friction between two disks

1. Homework Statement This problem was originally posted on Physics Problems Q&A: http://physics.qandaexchange.com/?qa=616/friction-between-two-disks 2. Homework Equations Second Newton's law for rotation: $$\tau = I \alpha = RF$$ 3. The Attempt at a Solution I tried to solve this...
11. ### Cylinder lying on conveyor belt

1. Homework Statement You buy a bottle of water in the store and place it on the conveyor belt with the longitudinal axis perpendicular to the direction of movement of the belt. Initially, both the belt and the bottle are at rest. We can approach the bottle as one cylinder with radius $R$...
12. ### Train on a rotating disk

1. Homework Statement A train stands in the middle of a rotating disk with an initial angular velocity of $\omega_i$. The mass of the train is m and the moment of inertia of the train-disk is I. At one point the train departs on a straight track to a distance R from the disk's centre. (R...
13. ### Curvilinear motion problem

1. Homework Statement A weight is suspended from a spring 50 cm long and stretches it by 1 cm. Take the other end of the spring in your hand and rotate the weight in a horizontal plane so that the spring is stretched by 10 cm. What is the velocity of the weight? (The force with which the...
14. ### Finding the Accelation Of A Body In Presence Of Frictions

1. Homework Statement A 60 kg block is pushed horizontally with just enough force to start its motion Accross a floor and the same force acts on it afterwards.The coefficient of static and sliding frictions are 0.5 and 0.4 respectively. Find acceleration of the body. Options 6m/s^2 4.9m/s^2...
15. ### B Why does friction play the role of centripetal force?

What makes frictional force the centripetal force of a car turning along a curve? As friction is the opposing force and acts anti-parallel so there is no component of frictional force towards the center,right? Then how can frictional force be centripetal force?
16. ### B What we mean in physics definition (quantity or property)?

Many books sometimes for example define energy as quantity and sometimes as property. Also the definition of energy is the ability to do work or the meter of the ability to do work ? we define for example force as a quantity or as some quality and then we quantify this ?
17. ### B What the equal sign means in physics

For example F=ma means that the definition of force is m*a or the quantity of left side equals to the quantity of right side or both ? or kinetic energy..we know K=1/2mu^2 but is this the definition of kinetic energy or just the formula to calculate it ?
18. ### I Trajectory of a particle under the given force

A particle of mass m in xy plane is attracted toward the origin with the force \begin{align}\vec{f} = - \frac{k^{2} m}{r^{6}}\vec{r}\end{align} where $\vec r$ is position vector of particle measured from origin. If it starts at position $(a,0)$ with speed $$v=\frac{k}{\sqrt{2} a^{2}}$$...
19. ### Velocity of a football with and without drag

1. Homework Statement A professional thrower projects a football straight up in the air. 1. Assuming there is no air drag on the football, find the speed of the football as a function of height as the ball goes up. 2. Assuming the air drag on the football varies linearly with speed, find the...
20. ### Kinematics on a frictionless incline plane

The situation: The mass is pushed up an incline with an angle of 1 degree with an initial velocity of 1 m/s, and it comes back down to its original position. The questions to answer: What is the total distance the object travels on the frictionless inclined plane? How long will the object...
21. ### Bead sliding inside a paraboloid

1. Homework Statement A bead slides under the influence of gravity on the frictionless interior surface of the paraboloid of revolution z = (x^2+y^2)/2a = r^2/2a Find the speed v_0 at which the bead will move in a horizontal circle of radius r_0 Find the frequency of small radial...
22. ### Classical mechanics: motion and acceleration

1. Homework Statement Referring to the attached diagram, the object ABCD is kept in an isolated system where it is under no external influence of any kind. A· An instantaneous force F acts along the edge BC of the block ABCD, where M is its mass, with its center of mass located at O...
23. ### Modified Block Problem -- Block on top and on the side

<< Thread moved to the schoolwork forums from the technical forums, so no Homework Template is shown >> The problem is a modified version of two basic block problems. This is my work so far, but I end up with two equations for acceleration from m1 and m2, I don't understand how to use both...
24. ### I Newton's first law of motion and Inertial Systems

I have just begun my journey in Classical Mechanics with the book "An Introduction to Mechanics" by Kleppner and Kolenkow. I find myself stuck at Newton's first law. The book presents Newton's first law as follows: "Newton's first law is an assertion that inertial frames exist." The book also...
25. ### Classical Source of Difficult Newtonian Mechanics Problems?

I'm looking for a source of harder mechanics problems, preferably with solutions. I'm supposed to use the Young and Freedman book, but I find it rather teadious and superficial; most problems don't match the difficulty and depth of the ones on the exam. I had my mid-term tests recently, and got...
26. ### A block placed in a horizontal hollow cylinder

1. Homework Statement A block is placed inside a horizontal hollow cylinder. The cylinder is rotating with constant angular speed one revolution per second about its axis. The angular position of the block at which it begins to slide is 30° below the horizontal level passing through the center...
27. ### Finding the magnitude of the force

1. Homework Statement A force F is applied on the bigger mass 'M', which results in the prevention of smaller masses M1 and M2 moving with respect to larger mass M. The mass 'M' slides smoothly on the frictionless surface. Find the magnitude of the force. The pulley is ideal also consider the...
28. ### How to differentiate b/w a conservative/non-conservative force?

1. Homework Statement How do we determine a specific force mentioned in a question to be conservative or non-conservative? 2. Relevant data Conservative force is a force whose work done does not depend on the path that is taken while doing it. Examples include electrostatic force...
29. ### I Newtonian energy integral and suitable boundary conditions

I have a (somewhat) strange energy equation which has the following form: KE = A + B W + C \exp(-D W), where A,B,D are known constant, C is an unknown constant to be determined and kinetic and potential energy are given by KE and W respectively with W\equiv W(r) i.e. is a function of...
30. J

### I How to model Solar System formation accurately and realistically

I've been working on a crude N-body simulator which allows N bodies of equal masses to interact gravitationally in 2 dimensions. My goal is to model the formation of Solar System. Each body is modeled as a circle with a radius as a function of its mass, in such a way that all bodies have the...