# Questions tagged [classical-mechanics]

For questions on classical mechanics from a mathematical standpoint. This tag should not be the sole tag on a question.

1,584 questions
Filter by
Sorted by
Tagged with
27 views

### Amplitude of waves in water after a disturbance [closed]

Suppose I have a perfectly circular pool which is five meters in radius, three meters in depth, and filled with water. Say I drop a steel ball with a radius of five centimeters into the middle of the ...
21 views

### How many ways can be used to find the contact force from a sphere which is over another?

The problem is as follows: Two homogeneous spheres are at equilibrium by the action of an horizontal force of minimal magnitude $F= 25\,N$, as shown in the picture from below. The sphere which is in ...
61 views

### How to find the elongation of a spring when it is tied to a brass bar over a tilted wall?

The problem is as follows: An homogeneous brass bar which goes from point $A$ to point $B$ has a weight of $300\,N$. The bar is suported over two frictionless surfaces as it is shown in the picture ...
34 views

### How to find the speed of a block after the collision with a swinging sphere?

The problem is as follows: A steel sphere has a weight of $40\,N$ and is anchored to a pivot in the ceiling as shown in the picture from below. The wire which connects the sphere to the pivot has a ...
16 views

22 views

26 views

### Two OCR A Level questions on $F=ma$

I just asked this on Physics.se, but the question was closed on there for "Homework-like questions and check-my-work questions are considered off-topic here, particularly when asking about specific ...
35 views

### How to solve simple pendulum equation and this equation ( $mv' + bv = mg$ )

I would like to know the steps to solve the simple pendulum (with small angle so it will be linear) and the equation of free falling mass with air resistance which is ( $mv' + bv = mg$ ). I just ...
14 views

### Problem with Generalized Momentum

I have a little problem: as we all know in Lagrangian mechanics generalized momentum is defined as the derivative in respect to $q$ dot of the Lagrangian. My question is: how can I show that this ...
6 views

63 views

### Energy conservation and solving for unknowns with a one dimensional string

I am trying to solve for unknowns $R,T$ when I have the following wave ansatz: $u(x,t)=\Re((e^{iwx}+Re^{-iwx})e^{-iwt}$, for $x<0$, and $u(x,t)=\Re(Te^{iwx}e^{-iwt})$, for $x>0$. If I impose ...
35 views

### Why homogeneous? [closed]

Why in the conservation laws ( I mean energy, linear momentum and angular momentum conservations) we consider time or space to be homogeneous _as the characteristic of inertial frame? Can anyone ...
35 views

### 4th-order Runge-Kutta method for double pendulum numerical solution

I am trying to numerically solve the equations of motion of the double pendulum system using the 4th order Runge-Kutta method by a C++ code. system diagram Energy equations required equations for the ...
23 views

### Express the total force as a differential equation [closed]

A particle of mass $m$ moves along a straight line (the $x$-axis) while subject to a force proportional to its displacement $x$ from a fixed point $O$ in its path and directed toward $O$ and resting ...
29 views

### Year 12 Maths - Mechanics - Resisted Motion - Getting stuck on the last part

I am getting stuck on part iv) of the question. Below are the question, photos to the solution and my working out respectively. Could someone please help me with this? Thank you so much! A particle ...
54 views

### Conversion of a vector field from Cartesian to Polar Co-Ordinate Systems

I understand that textbook questions are to be avoided here but I would like to request help from this forum. This a question in mechanics which involves what should be a fairly straightforward ...
22 views

### How do you find the centre of gravity using moments?

I'm just working through this example (Example 2), using moments and resolving forces to find the centre of gravity of three particles. I understand resolving the forces and finding $\bar{x}$, but I ...
16 views

### Impulse and change of direction

A particle $P$, of mass $0.5$ kg, is moving with velocity $(4i+4j)$ m/s when it receives an impulse $I$ of magnitude $2.5$ Ns. As a result of the impulse, the direction of motion of $P$ is ...
40 views

### VERY HARD Collision Questions, (Further Maths A Level)

Ques I've attached the question using the link since it would be too hard to format myself. Essentially, What i've done so far is said; From start to wall 1, the time is $\frac{d}{u}$ From Wall 1 ...
When asked to find energy, when do you use $E=\sum_i\dot q_i p_i−L$ as opposed to $E = T+V$, where $T$ is the kinetic energy and $V$ is the potential energy? This is for Lagrangian problems.