Recent content by Oomph!

Hello. In my bachelor thesis I make motivational video experiments in physics (for high schools). I want to mention some already existing videos. I know videos from our country or channels from YouTube. However if I'm looking for some videos from Universities or professional organizations...

Hello. I have some problems with making Lagrangian. I need your advice. 1. Homework Statement I have this situation: Consider the circular path is intangible and without friction. I have to find Lagrangian for coordinates x and θ. Homework Equations [/B] L = U - V The Attempt at a...

Hello. I solve this problem: 1. Homework Statement The particles of mass m moves without friction on the inner wall of the axially symmetric vessel with the equation of the rotational paraboloid: where b>0. a) The particle moves along the circular trajectory at a height of z = z(0)...

Do I really need the Lagrangian? When I read the study text, there was Lagrangian only in Lagrange's equations of the second kind, not in Lagrange's equations of the first kind. And I wrote there Lagrange's equations of the first kind, because in my task was, that I have to use this. My study...

Homework Statement Hello. I have this problem: I have a ring which is sliding along a wire in the shape of a spiral because of gravity. Spiral (helix) is given as the intersection of two surfaces: x = a*cos(kz), y = a*sin(kz). The gravity field has the z axis direction. I have to find motion...

Okay. Thank you very much for your advices.

Ok. Thank you. I tried this: Conservation of energy: E1=E2 ... energy far away from the Sun is same when the comet touch the surface of the Sun 0.5*m*v12 = 0.5*m*v22 - m*M*G/R m... mass of comet, M... mass of the Sun, v1... velocity of the comet far away from the Sun, v2... velocity of the...

So, the second attempt: Angular momentum far away from the Sun: |L(1)|=m*v*r*sin 0° = 0. Angular momentum when it touches the surface of the Sun: |L(2)|=m*v*R*sin 90° = m*v*R, where R is radius of the Sun. I said that I have to use the law of conservation of angular momentum. So |L(1)| =...

The comet moves on hyperbolic trajectory and in the hyperbolic focus is the Sun, isnt't it? Far away, the angle between velocity and position vector is near to 0°, so angular momentum is |L|=m*v*r*sin 0° = 0. It it just touches the surface of the Sun, the angle between velocity and position...

I can't use conservation of linear momentum because the system rotates. I have to use the law of conservation of angular momentum. When the comet moves along the ellipse, the velocity is perpendicular to the position vector in the aphie and perihelia. I could write: m*va*aa=m*vp*ap, so...

I really don't know how to create second equation :( Impact velocity is perpendicular to surface of Sun?

Hello. I will make some physics videos for children to bachelor thesis to popularize physics. I have a lot of ideas. However, I want to make same experiments more interesting. But I don't have any good idea right now. I think that there is a lot of creative people which could help me and give me...

So, at the beginning it has just kinetic energy and when it hits, energy is sum of kinetic energy and potentional energy? Ek(1)=0.5mv^2; Ep(1)=0; Ek(2) =0.5mu^2; Ep(2)=-G*mM/R v... velocity at the begining; u... velocity when it hits; m... mass of the comet; M... mass of the Sun; R... radius of...

When is the comet at some great distance, the total mechanical energy is only the kinetic energy, isn't it? So, E=0.5mv^2. If it hits at speed u, it is same? Maybe the law of conservation of momentum.

Hello. 1. Homework Statement I have to find formula for effective cross-section (σ) of catching a comet with the Sun. I know mass of the Sun (M), radious of the Sun (R) and initial velocity (v) of the comet (at a big distance from the Sun). Homework Equations σ=πb^2, where b is on the...