Feynman lecture on physics Definition and 20 Threads

TL;DR Summary: Solutions to an exercise coming from the famous "Exercises for the Feynman lectures on physics". I'm stuck on an exercise. "A mass ##m## (kg) hangs on a cord suspended from an elevator which is descending with an acceleration of ##0.1g##. What is the tension T in the cord in...

It seems to me that the answer should be v = V((1+sinθ)i -(cosθ)j) intuitively since ##V_x## should be zero at θ = −π\2 and should be greatest when the angle is 90 degrees. Similarly, the component of velocity in the y direction should be greatest when the angle ##\theta## is 180 degrees and...

Here is what Feynman says, "Suppose we have two equal masses, one moving with velocity v and the other standing still, and they collide and stick; what is going to happen? There is a mass 2m altogether when we are finished, drifting with an unknown velocity. What velocity? That is the problem...

I was reading The Feynman Lectures on physics http://www.feynmanlectures.caltech.edu/I_23.html chapter 23, section 4. In it he derives the equation for current when inductor, resistor and capacitor is connected in series with an alternating voltage source, he derives this equation:-...

I’m having trouble understanding section 30.1 of FLP Vol 1. Particularly the first figure is causing me struggle. I understand magnitude and phase, such as fig 29-9 when 2 waves are added to get an effective resultant vector. But I’m struggling to see how equation 30.3 is applicable when it’s...

How ellipse appear from only lines in a circle and addition to Kepler's law.

Homework Statement [/B]Homework Equations 1/s+n/s′=1/f where s is distance from source to diffracting surface, s' is distance from diffracting surface to focus, f is the focal length, n is the refractive index. The Attempt at a Solution Since we have parallel beams, we have s = infinity so the...

Homework Statement I tried to understand the problem b) and c).[/B] Homework Equations Faraday's law: ∇xE = - ∂B/∂t emf ε = Bdv Force : F =ma, Lorenz's force F=q(vxB) ==> ma = IdB Power : power of battery = εI, mechanical power of the wire = Fv The Attempt at a Solution I think I solved...

Homework Statement This is the exercise 10.6 from Feynman lectures on Physics 2. Two coaxial pipes of radii a and b(a<b) are lowered vertically into an oil bath. If a voltage V is applied between the pipes, show that the oil rises a height H. Show that H=(V^2)(κ-1)ε_0/[ln(b/a)ρ(b^2-a^2)g] where...

Homework Statement Homework Equations The Attempt at a Solution The moment of inertia before collapse is for each rod: BEFORE COLLAPSE:[/B] Ib = ∫(L2 + x2) dm = m/L ∫(L2 + x2) dx = 4/3 * m * L2 We have 8 of these plus the inertia of the mechanism, giving a total I, It = 8 * Ib + Ik =...

Homework Statement Homework Equations Conservation of momentum: m1*v1 + m2*v2 = k Conservation of mech. energy 1/2 * m * v^2 + m * g * h = k The Attempt at a Solution Why can't i just use conservation of energy to solve this one? I know that the bullet contains all the kinetic energy before...

Homework Statement Homework Equations F = ma The Attempt at a Solution The gravity pulls on m with a force Fg: Fg = m*g This force is directly translated into pulling the total mass m+M with an acceleration a: (m+M)*a = Fg <=> a = Fg / (m+M) = m*g / (m+M) with this acceleration, we can...

Homework Statement "A mortar emplacement is set 27,000 ft horizontally from edge of a cliff that drops 350 ft down from level of mortar...It is desired to shell objects concealed on the ground behind the cliff. What is the smallest horizontal distance d from the cliff face that shells can reach...

I am no able to understand the reasoning of Feynman in deducing that it is impossible to build a machine that will lift a weight higher than it will be lifted by a reversible machine. I am also not able to understand what reversible machine is. So, please help me.

I was admitted to a very good undergraduate physics program (Columbia University), but I think I would like to take a gap year (defer my admission) to prepare my self better. I do feel a bit intimidated as I come from Colombia and I would prefer it if I could further my studies before going to...

Hello! I hope this is the proper forum for my question(s). English is not my native language, so I apologize in advance for language mistakes. In Feynman Lectures on Physics, there is a chapter about the conservation of energy. The first part, which deals with the definition of energy, I...

Hi all, I have a little problem while reading Feynman lecture note volume 2, chapter 40, section 40-3. In that section Mr Feynman talked about Bernoulli equation and a example of a filled water container. In high school we learned that if we drill a hole near bottom of container, we can get...

Hello to everyone, merry christmas and happy new year! I was trying some exercises on the Feynman Lectures, on the topic of statics, and I came across with a problem which, simplified until where I am stuck, asks for the tension of a cable perpendicular to a bar with a weight on the top of it...

I have read that Feynman Lectures on Physics is pretty good; however, I also read it isn't a replacement for a good textbook. So I wanted a good physics(high school level) textbook that I could read Feynman Lectures on Physics along beside it. Regarding mathematics, I have completed Calculus I...

I have the books and audios. But I have yet to find the videos. I am wondering whether they exist.