# Search results

1. ### Hinged rigid beam vs mass free fall

Acc. is same for free falling bodies. Take torque about the stationary end of the rod and find angular acc. ## \alpha = \frac{3g\cos\theta}{2l} ## Here ##\theta## is the angle with horizontal of rod, so any point on the rod beyond ##\frac{2l}{3g\cos^2\theta}## will have vetical acc. more than g...
2. ### Writing a book so im learning about things, i have some general questions please read

Okay so stop relatin quantum physics and biology because i dont know anthing about later cells are nearly 6000000000 times large(or even larger) than electron on which uncertainity principle is applicable significantly and as the size increase the uncertainity become less dominant and is...
3. ### Equations needed for force required to lift water Take 2

Hi Mark Nutley, well if have lots of time then CONGRATULATIONS, you will be wasting least amount of energy,(when you speed some thing you waste energy in speeding things though you just want to go to your next position and then you waste energy in slowing it down at its final postion to stop)...
4. ### Can I see sea-level sunset if something lower than me is blocking my sight?

Can you see the sea horizon? if yes, then yes you will see it. And if no, then it is possible that you see sun which is on the tangent of earth at the sea(due to atmospheric refraction). But even if it is so you will see the sun at sea but not sea itself then i dont think it is a sea sunset...
5. ### Moment of Inertia Experiment

Hi welcome to phy forum(everyone does that so i did it too for your first post) Well you dont know the L now but i hope that you know the speed at which the dancer is expanding her/his arms(& her mass and her arms mass....etc). So you will calculate L(t) as a function output of time and you...
6. ### Equations needed for force required to lift water Take 2

HI!! Well it is strange that you are doing fluid and have not covered work energy. Anyways what is the approach you are familiar with or trying to think of. Your question is not complete, see lifting water (to a distance)needs not only force but an amount of time on which it is applied...
7. ### Newtons Law of Gravitation

I think that Averforde might be saying that if we hold a rod then the force on it might be less (or might be other way, i have totally forgotten my result and calculation),though negligible, than that of if we put it horizontally (rotated by its MIDDLE). Which you can find out newtons...

YES, so it by instantaneous axis of rotation. search it up on google if you dont know about it. it becomes very easy
9. ### Lens silvered at one face

Actually it does. Just do it logically. I think that powers add because of formula being 1/v -1/u , so when you add p2 the image of 1 is oblect for 2 so basically it cancels out .p1 +p2 is just using the lens formula ignorantly . Ensure that proper sing and conditions are followed.Hope that helps
10. ### Recurrence relation

pre multiply 5,-6,1,0 matrix on both the sides(to the k equation) and you will have your proof
11. ### Doppler effect and amplitude

i am sorry for my ignorance. i actually once wondered about speed of light in high refractive index but had never related it to Cherenkov Radiation. so thanks.
12. ### Eccentricity of orbits and gravitational energy

I am not going to start an argument but 1) i never asked to solve the question, my interest was in the approach ,which i thankfully got and was also the reason that i didn't bother about (2-K^2) part. It was just an eg. to indicate what was my topic. 2) i was writing it from my memory and...
13. ### Question about magnetic fields and magnetic forces

Well technically one thing never touches another thing(excluding nuclear reaction which i do not know much about). and idont think that it works the same way at electronic level , you have to consider the shape and orientation of orbitals and everything ,anyways in your case we don't even...
14. ### Doppler effect and amplitude

well considering that we cant reach speed of EM waves it is safe to say that there are no chance of EM boom but what i think is what happens in case of transverse wave when its source moves faster than the speed of wave? .eg in case of wave on a string (i cant even imagine) As far as the...
15. ### Eccentricity of orbits and gravitational energy

Okay i found the question it does not say anything about the direction of velocity to be tangential or otherwise, so WHY are we taking it as tangential i have tried taking it at theta but it just didn't solve. and sorry it has been a while since i used r' notations.
16. ### Eccentricity of orbits and gravitational energy

two things 1) what is r' = 0 2)i understand tha r1 is the initial radius, but in last step you have used it for min distance which it cannot be becauseat min distance all its velocity must be perpendicular. Thanks btw!!
17. ### Eccentricity of orbits and gravitational energy

hello. i recently came across this question in which a satellite is put into orbit at a point around a planet with velocity 1.2V, where V is the speed for a circular orbit at that point and they ask for ratio of max to min distance. [Ans. 2.57] what i want to know is how do we relate...