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1. Throwing a Knife

They say that a rotating knife thrown is more dangerous than a knife thrown straight I find it weird If the knife is rotating, it will experience more air drag than if thrown straight which will also depend on plane of rotation(For some reason, I don't know, it experiences more drag if...
2. B Creep and its effects on a material

What I do not get is why should a stress much lower than yield point cause deformation in a material? If temperature is high intermolecular attraction is reduced and thus even low stress can deform things. But if it is low Then a force lower than yield point should be less than intermolecular...
3. Moment of Inertia of a 4 rod system

This was the question (The line below is probably some translation of upper line in different language) For disc it was ma^2/2 For ring it was ma^2 For square lamina it was 2ma^2/3 For rods It was different Please explain Thank You🙏
4. Work, Energy, Power Question

I tried to solve it by integrating force from 0 to L dF=dm.g where dm=λdx And then I multiplied it with velocity to get power because velocity is constant ∫(vdF)=v ∫(dF) But the book used integration to find work done and divided it by time for power My answer was λlgv(Option B) Giving...
5. B Projectile motion — Thinking about forces on a curve ball

When a ball is thrown such that it moves in a curved trajectory in the horizontal plane, it amuses me to think of its dynamics. In motion of a ball thrown upwards the force of gravity gives it a parabolic trajectory However when the ball is thrown to curve and hit a target, (in the horizontal...
6. I Atomic Structure -- Why does transition energy decrease with increase in orbit number?

I have read that an electron requires certain minimum energy of threshold frequency to move an orbit However the energy needed decreases with increase in shell number The transition energy is reduced with each orbit For example The energy to shift an electron from 1st to 2nd orbit is much...
7. Dynamics of a double atwood machine

I think the equations should be 𝑇−𝑚2𝑔=𝑚2𝑎1 𝑚3𝑔−𝑇=𝑚3𝑎1 𝑇1−𝑚1𝑔=𝑚1𝑎2 2𝑇−𝑇1=(𝑚2+𝑚3)𝑎2 P.S.- My textbook assumes T1 = 2T. I don't understand why that is so.