# Tagged Questions

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.

112 views

### Will a heavier or lighter tank shell / bullet/ etc. travel further given the same starting energy?

Let's say I have for example two tank shells, both being the same size and having the same shape. Let's say the starting energy is 100kg*m/s^2, and the one shell is 1kg, the other 25kg. 1kg * 10m/s^...
198 views

### Damping Constant for a Ball Rolling in a Bowl

How would you find the damping constant of a ball rolling without slipping in half of a sphere? I know how to find the period of the oscillation, but how would I find the damping constant ...
450 views

### Car driving / falling off of a cliff - will it land upright?

In a recent episode of The Walking Dead, a van was pushed off of a bridge and flipped once and landed upright, on all four wheels. Assumption: the ground and cliff are both flat. Will a vehicle ...
2k views

### Kinetic energy of an object at rest

Why don't we consider that an object on Earth has kinetic energy as it is also moving at the rotating speed of Earth?
120 views

### Maximum velocity on Unbanked roads and why should friction be more than centripetal force? [closed]

Why is maximum velocity on unbanked circular road given by $\sqrt{urg}$ where $u$ is coefficient of friction, $r$ is radius of circular track and $g$ is acceleration due to gravity? Why should ...
121 views

### Coupled ODEs that model a quad rotor

I am working on modeling the vibrations of a quad rotor. The arms that support the rotors are fixed to a center plate; that is, it is pretty much a cantilever beam with an end load. Since this is the ...
469 views

### Liquid placed in a rotating cylinder

The Question A closed vertical cylinder is filled with an incompressible liquid of mass m completely. The cylinder is now sealed from all sides and rotated about ...
2k views

### Calculating the moment of inertia in bifilar pendulums

I'm an A2 student, and I've been looking into how experimental and theoretical determined mass moments of inertia differ. I came across a method (search Youtube for Measuring Mass Moment of Inertia - ...
145 views

### Question about massive spring and SHM [closed]

A mass $M$ is resting on the end of a spring with constant $K$. The mass of the spring is $m$, and the displacement of each element of the spring is proportional to the distance from the fixed end of ...
151 views

### What motion can emerge in a still universe? [duplicate]

I consider a very large non homogeneous cloud of dust in isolation. No external gravitational interactions. It is initially completely still and start collapsing under the its own gravity. Can the ...
3k views

### Friction Between Liquid and Solid Surface

How does friction between liquid surface and solid surface differ from viscosity, the friction between liquid and liquid surfaces? Also has a word describing the process been invented or is liquid-...
2k views

### Velocity of car down an Inclined Plane

I was learning to make a car game and came across this situation where my car is on an inclined plane. It's initial velocity is 0. Now, the problem is that my memory serves me this formula to ...
48 views

### Where is the direction of kinetic friction in this question?

Suppose there is on object of 20.0kg sliding to the right. A person exert a force of 30N left on the object. The object has an acceleration of 2.5m/s^2 left. What is the magnitude and direction of ...
48 views

### Relating Angles in Elliptical Orbit

I've been trying to model the orbit of a comet of arbitrary mass around our sun from having a known initial condition with $r_0, v_0$ with angle $\alpha$ at $t_0$ around our sun. I've been able to ...
151 views

### Rolling without slipping [closed]

A uniform, solid cylinder of mass $m$ and radius $r$ rolls without slipping down a plane, inclined at an angle $θ$ to the horizontal. You may assume, without proof, that the moment of inertia of the ...
203 views

### Rate of acceleration for two hanging masses in two experiments

I conducted an experiment where two masses of different weight were attached by a string and fed through a pulley. The difference between the masses was $0.025\: \mathrm{kg}$. The lighter mass was ...
6k views

### Physical meaning of the angular momentum

Still reading Classical Mechanics by Goldstein, I'm struggling on a very basic notion: angular momentum. I physically understand it as the momentum of an object rotating around something given a ...
95 views

### Restoring force surface method for nonlinear system identification

I am working on nonlinear system parameters identification using the restoring force surface method (or the force-state mapping method). I found some references in which the method is explained but I ...
231 views

88 views

### Newton's gravity formulas for ellipses

A few times I've come across formulas, which are identical for circular and elliptical orbits, except that for the second ones you substitute $r$ with $a$, where $r$ is the radius of a circular orbit ...
108 views

### Is change in kinetic energy invariant?

Consider the inelastic collision between two bodies. This question follows on from this: Is the coefficient of restitution frame independent and energy conservation?. One of the answers to this ...
286 views

### Who plays the role of centrifugal force in an inertial frame of reference?

It is noteworthy to quote a sentence from my book, It is a misconception among the beginners that centrifugal force acts on a particle in order to make the particle go on a circle. Centrifugal ...
272 views

### Why do you have less control over a bicycle with a broader steer?

I recently had an argument with someone on why a bicycle with a broader steer gives you more control. We both had different answers to this question and neither could convince the other. First a ...
325 views

### What's the difference between frequency domain and time domain spectra?

If I have a mechanical oscillator and want to observe the dynamical behavior of the oscillator, is there any additional information to observe it in time domain and frequency domain? Normally, we ...
727 views

### Where does the force to stop a constant velocity object come from?

If a ball hits a wall at a constant velocity, it will slow down and eventually come to rest. Since the ball was at constant velocity, it was not accelerating, and so there was no force. Also, the ...
135 views

### force acting perpendicular through a rotational axis

This seems rather basic to prove mathematically but i am second guess my intuition. Say you have an object in rotation and a force acts on it through the axis of rotation perpendicular to the axis of ...
3k views

### How does a roller coaster car stay on the track on a curve [closed]

Say a roller coaster car is going up a ramp to a drop. At some point it needs to traverse a curve to get to the drop. In general, since the car is constrained to the rail, how is it able to move ...
478 views

### Could Galileo ever prove that $g$ is the same for a feather and a hammer?

Do you think he could have possibly found a way to make a feather and a hammer touch ground simultaneously, as they should, according to gravity? Can you make up a device that avoids air resistance? ...
302 views

### How would the Sun's gravity affect us if we weren't in orbit?

So since we're in orbit around the sun, we are basically in free-fall. From what I understand, this means that we don't feel the gravity of the Sun like we do the Earth. Just like astronauts on the ...
79 views

### Ballistic Pendulum question?

I am answering a question regarding the ballistic pendulum, and the teacher gave this worksheet. I have figured out both t (time) and the change in y. Where I am getting confused is where he wrote out ...
231 views

### Angular momentum

The satellites are revolving around a planet in circular orbits by themselves (no external source to maintain their speed). Are we able to make them revolve in elliptical orbits by themselves? Do ...
72 views

### Reduced mass and energy representation?

If we have a gravitational system where $m<<M$ then we can write down the energy of $m$ as follows: $$E=\frac{1}{2}m(\frac{dr}{dt})^2+\frac{L^2}{2mr^2}-\frac{GMm}{r}$$ but if $m$ is not small ...
69 views

### Where does the block get the energy from?

Let there be a block of mass $m$ on a frictionless surface. A boy of mass $M$ exerts an invariant force $F$ on the block & does positive work on the block by displacing it by $d$. By Law of ...
423 views

### A two-masses-three-springs system [closed]

Question: If two identical masses are attached to two walls facing each other and the two masses themselves are connected by a third spring (all springs have same initial length and spring ...
7k views

### Build a ring around Earth, then remove the supports

What would happen if we decided to build a giant ring that managed to wrap around the whole world, end to end that was supported with pillars all along the ring and then the supports all suddenly ...
47 views

### Why do we have to use an integral in this scenario to figure out $v_{max}$? [duplicate]

$$\int_0^R mg\frac{r}{2}dr=\frac{m}{2}v_{max}$$ and can't write $$\frac{m}{2}v_{max}=mgR$$ don't we usually equal potential energy to kinetic energy? A stone is falling through a tunnel towards the ...
235 views

### Cart moving on frictionless tracks in the rain

I am working on a question in which a cart is moving on frictionless tracks and it begins to rain. The cart has a drainage hole to let the rain out at exactly the same rate at which it enters $k~kg/s$....
278 views

### Simple harmonic motion frequency [closed]

I already did part a and b by using kinematics but I'm stuck for the next part A particle moves along the x axis. It is initially at the position 0.300 m, moving with velocity $0.070 m/s$ and ...
159 views

### Friction force in rolling motion

In rolling without slipping motion we know that the friction acting is static friction and so we treat it as an unknown while solving equations of dynamics. Question: Is the static friction during ...
478 views

### Why do non-circular oscillations have angular frequency? [duplicate]

Why so the oscillations which are not circular also have angular frequency which is a quantity related to the circular motion? I have referred many articles related to simple harmonic motion where ...
413 views

### Is there a normal downward force here?

Now through my understanding, there is a weight force that points downward on block A, also another weight force that points downward on block B. Between block A and block B, there is two normal ...
1k views

### Why doesn't centrifugal force appear on an FBD for a car on a banked track?

Suppose you wish to find the max speed at which a car can travel on a banked curve of radius R and angle theta to the horizontal and coeff. of static friction mu. I don't understand the relevant ...
3k views

### The direction of frictional force in smooth rolling motion

I want to ask about the direction of frictional force in smooth rolling motion which means the rolling object doesn't slide on the surface. Here is the first case, the wheel rolls to the right so the ...
327 views

### Banked Curve with friction

Suppose you have a car traveling on a banked curve with friction. The curve makes an angle $\theta$ with the horizontal and has coefficient of static friction $\mu$. Suppose we wish to calculate ...
921 views

### “Bump and Go” toy car mechanism [closed]

Can anyone please explain how the bump-and-go mechanism works in "old-school" toy cars? It's the one that uses a single swivelling wheel in the front, and when resistance is encountered (due to the ...
56 views

### Equations for displacement

I have a pendulum which is manually operated and so does not slow down. It is going at a frequency of 10Hz. It has a maximum angle of 25 degrees and length 10 cm. What are the equations of ...
783 views

### Magnitude of work

I am a little bit confused on the concept of work. By definition, work done by a constant force of magnitude F on a point that moves a displacement s in the direction of the force is W = Fs. So lets ...