1. ### B Two masses collide with a spring -- Find the final positions/velocities

Let's say you have two masses on either side of a spring. Mass 1 is connected to the end of a spring. The spring itself has no mass. Mass 2 is free in space. So you have: [M1]-[spring] [M2] So it's more descriptive, I'll name the variables like you might in programming. Let's define...
2. ### B Testing the effect of Gravity at home....

Hi .... air resistance is the reason that objects of different mass fall to earth at different speeds. In a vacuum all objects fall to earth at the same rate regardless of mass. OK - I get it but all the experiments that illustrate this tend to rely on tall buildings or massive vacuum chambers...
3. ### Newton's Law of Cooling Question- relationship between the temperature of the substance and the initial room temperature

Through the research that I conducted is that I wasn't able to find actual supporting answer to this question. I struggle with Physics and math and because of Coronavirus my school has shut down meaning I don't have access to my teachers or tutor. The main line that i am thinking is that if it...
4. ### Heating a soup (solving this problem with a DE)

I'm having quite a bit of a problem with this one. I've managed to figure out that ##T_0 = 0##. However, not knowing what ##q(t)## is bothers me, although it seems that I could theoretically solve the problem without knowing it. For ##t>t_1##, integration by parts gives me ##T = Ce^{-t/10}##...

6. ### Three masses, a string and pulley and a table -- solve for the acceleration

Let T be the tension in the string, a be the acceleration of mass 2m, 2a be the acceleration of mass m T = (m) (2a) ---eq(1) The mass 3m will come down with acceleration a’ = (a+2a)/2 = 3a/2 3mg - 2T = 3m . 3a/2 from equation 1 3mg - 2(2ma) = 3m . 3a/2 thus a = 6/17g thus acceleration of 3m...
7. ### B Can someone please explain this paragraph from A Brief History Of Time

what does it mean when you say the stars all fall in on each other?And what does the line uniform distribution of stars outside this region mean?and what does this line mean- again fall in?what does fall in mean? would really appreciate some help in understanding the meaning in simpler words...
8. ### Force as a function of time

Hello, I have the force defined as a function of time, where F=A-Bt and A=100N, B=100Ns-1. I have to determine, how long it will take for object to stop, if t0=0s and v0=0,2ms-1 and mass of the object is m=10kg. Can somebody please help me with this, because I'm having hard time with this task.
9. ### I Understanding forced motion in space

Hello, Can you please explain the analogy oft quoted to explain the concept of applied motion to objects in space, which goes as follows : 1. You are standing on a skateboard or sitting in a boat floating on the water, holding a bowling ball. 2. You throw the bowling ball towards the back of...
10. ### I Relationship between the Volume of a balloon and the time it takes to deflate

I would like to ask a question on whether there is a proportionality between volume of a balloon, and the time it takes to deflate. I have conducted several balloon hovercraft experiments. I need to find the relationship between the amount of air pumped into the balloon and how long the...
11. ### Formula for fictitious moments

Hi All, Everyone knows so called "fictitious" forces, also known as "inertial" forces. They are forces felt by some mass point placed in a non-inertial frame. For example: a ball in a moving car or in a carousel. Maybe most intuitive fictitious forces are centrifugal forces, but there are also...
12. ### I Gram as weight?

Ok so I've asked my physics teacher and a statics teacher as well and I couldn't get a straight answer from either. So here's my questions... Correct me if i'm wrong, but isn't the gram a unit of mass? Not weight? I thought that for mass to become a unit of weight, it has to have to...
13. ### A Inertial Frames

This question concerns inertial frames. I am aware that an inertial frame is one that is not accelerating. I am aware of an alternative definition: it is one on which no forces are applied. (Yes, they are the same thing.) I am also aware of the d'Alembert "forces" that appear when a frame is...
14. ### I Feynman QED

I recently started reading Feynmans book QED. There are a couple of questions I have regarding his theory on the percentage of light that is reflected of two surfaces of glass. My question is as follows, A piece of glass in fact has four surfaces. The front of the glass the back side of...
15. ### I Is quantum mechanics formulated from 1st principles?

I was surprised recently to learn that one of the reasons both Newton and Einstein were so revolutionary was that they performed a neat mathematical trick. For Newton, it was the mathematical derivation of Kepler's laws from Newton's laws of gravitation and motion. For Einstein, it was the...
16. ### I F=ma -- How did Newton find this?

I did some googling but only found nothing to answer my question. How did Newton come up with this formula, literally/physically? Did he have chunks of stuff and moved them around, then logged various results. Then maybe he played around with various formulas and saw which fit the data?
17. ### I Contributions to Dynamics - China

Hello, To ensconce this question properly, we know that some of the major contributions to the discipline of rigid body and classical particle dynamics came from: Newton, Euler, Hamilton, Lagrange and so on... (no need to suggest other western names right now - I am aware of them). However I...
18. ### B Experiment on Newtons First Law

I am wondering if anyone knows of a good resource to see Newtons first law in action. For example, a block being pulled by increasing force until it moves?
19. ### Tension in a rope

Homework Statement I have a rope held by a hook, which is attached to the ceiling by a chain (with an angle theta), in one side, the rope (with an angle alpha) is attached to a a wall, in the other side, the rope is carrying an anvil of 110 Kg mass in vertical position. What is the tension in...
20. ### I Why do objects with mass attract each other?

In most cases, we know why things happen. Protons can stick with each other because of the strong nuclear force. There's all kinds of forces and we know mostly about why they occur and how they are transmitted. But I don't understand gravity. Why do objects with mass attract each other ? I know...
21. ### I Force to seperate two magnets

Hi, i have a question. I need to know how much newton it takes to seperate 2 magnets or a magnet from a from a piece of metal. I've bought a spring scale that measures max 50 gram, so very accurate. Now what if i attach the scale to the magnet and i pull it horizontally just enough to...
22. ### Man's weight on a railroad car

Homework Statement The problem relates to the subject of torque and angular momentum: A man of mass ## M ## stands on a railroad car that is rounding an unbanked turn of radius R at speed v. His center of mass is height ## L ## above the car, and his feet are distance ## d ## apart. The man is...
23. ### B How does a hummingbird hover?

Hello, I understand that Newton's laws of motion can explain how a hummingbird is able to hover in front of flowers. There is one question I have in particular, which is, Is the lift generated by the wings of the bird and its weight force an example of a pair of Newton's third law forces? They...
24. ### A Two-Body-Problem with Changing Mass

Hi, I would like to ask you what happens when you change (gradually) a mass of one body in a classical two-body-problem. May it lead to such results? Many thanks. Flor
25. ### B Why were Newton's laws of motion discovered so late?

Hi, I had a thought recently which gave rise to a rather interesting query. A helicopter works and is able to fly due to Newton's third law of motion. The propellers rotate at a high speed and exert a force on the air beneath them. By N3L, the air therefore exerts an upwards force on the...
26. ### B F=ma -- True or an Illusion...

Imagine, There's a ball in deep space traveling with a constant velocity of 25m/s and is having mass 25kg. Now as I said, ball is traveling with a constant velocity that simply means acceleration=0 and now if we calculate the force with F=ma we will end up with 0. But if that ball collide with a...
27. A

### Newton's Rings and Thin Film Interference

Homework Statement A total of 31 bright and 31 dark Newton's rings (not counting the dark spot at the center) are observed when 550-nm light falls normally on a planoconvex lens resting on a flat glass surface. How much thicker is the center than the edges? Homework Equations 2t = mλ 2t =...
28. ### B Shape of water in a rotating container along A vertical axis

Hi! I am currently working on a project that includes rotating a water-filled container. The container is NOT spinning about its vertical axis, but about the vertical axis of the rotating disc. I am aware that the surface shape of water in a rotating bucket takes the shape of a parabola when it...
29. ### Particle moving down a cone (Newtonian formulation)

Hi, This a Classical Mechanics problem I've been trying to solve for a few days now. I cannot use Lagrangian or Hamiltonian formulation, it must be solved using classical Newtonian formulation. One must determine the equations of movement of the particle in cartesian, spherical and cylindrical...
30. J

### I Torque and force on a tire iron

So I was curious about something. Having a flat tire today and having to change my tire made me wonder. I understand torque and force are 2 different things though related they have separate meanings. So my question is if I have a 2 foot tire iron and I am torquing my nuts. Lets say they...