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location Denmark
age 26
visits member for 4 years
seen 14 mins ago

"If you can't explain it simply, you don't understand it well enough" - Albert Einstein

"What he said ^" - Steeven


1d
comment Kayaking against the wind is faster than with wind in my back?
I am not sure if there is anything to this, and I cannot simply say that there isn't. But observations of speed on sea are really difficult, and the human eyes and ears are terrible comparison devices. twitter.com/neiltyson/status/276808419925712896 May I ask if you have made an actual measurement by kajaking a distance while measuring the time, or is the observation based on you eye-witness testimony alone?
1d
revised Right hand rule confusion
added 8 characters in body
1d
comment what are dimensions?
How would you use such numbering system for an open coordinate system with infinite x axis and y axis?
1d
comment Fleming's right hand and left hand rule
You have to use your right hand on your example. It is simply a matter of which rule to use for which expressions/situations.
1d
comment Vertical Circular motion - Tension and velocity
That the tension in the rope must be 0 for this to happen is simply a consequence of the fact that as long as there is tension, the rope is apparently holding in the body. And when the rope is pulling in the body, the body can only move in a circular path. When the tension is 0 then the rope has just become slack.
1d
comment Vertical Circular motion - Tension and velocity
Yes, the body will then fall as a projectile. Since the tension is gone, only gravity affects the body, so the body falls as if there was no string. Only with the string gets tight again and has tension, then the body will be force back into the cirular path.
1d
answered How the electric potential of a charged body depends on the surface area of the body?
1d
answered Vertical Circular motion - Tension and velocity
Aug
29
comment How to calculate the linear speed without angular velocity?
@user86008 force depends on mass This is not correct. I can easily apply different forces on the same mass. force depends on [...] centrifugal force Not understood. Centrifugal force is never a force to consider, only a way to explain intuitively what is going on. Are you saying it is impossible to rotate anything horizontally Yes I am. You can never reach exactly $90^\circ$. Maybe $89.9^\circ$ for light objects, but never exactly $90^\circ$.
Aug
29
answered Block over a Block Problem.
Aug
29
comment How to calculate the linear speed without angular velocity?
@user86008 How do you mean "quite possible"? To have an angle $89^\circ$ would require a tremendous force to avoid that the stone falls vertically. Try to swing a ball on a string over your head. It gets very hard if you try to make a flat circle.
Aug
29
comment Block over a Block Problem.
Is it the coefficient of static friction or of kinetic friction that you have?
Aug
29
revised How to calculate the linear speed without angular velocity?
added 96 characters in body
Aug
29
comment How to calculate the linear speed without angular velocity?
I am not sure I follow? $m$ is the mass you just asked about.
Aug
29
revised How to calculate the linear speed without angular velocity?
added 292 characters in body
Aug
29
comment How to calculate the linear speed without angular velocity?
Well, it can't... You are right. BUT if you keep it as an unknown and carry on, then you will see that $m$ cancels out with the $m$ in the $T_{cen}=ma_{cen}$ part.
Aug
29
answered How to calculate the linear speed without angular velocity?
Aug
29
comment How does pressurized gas constantly push?
Let me add a note: A good example is always a simple table . The table must exert a constant force all the time to hold up a book lying on it. No energy is spent to do this.
Aug
26
comment Is it possible for a conductor initially, not to have a charge?
@Ilawliet Well, conductors contain electrons which are electrically negative individually. But as a whole you should rather think of a container as having a negative (net) charge if it has too many electrons, and a positive (net) charge if it has lost electrons
Aug
26
comment Frictional pulley
Why is friction horizontal? I would rather consider it a force that causes a counteracting torque. If you provide a simple sketch of the setup it would be much easier