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location San Mateo, CA
age 59
visits member for 2 years, 11 months
seen 5 hours ago

6h
comment Can a force applied to a wheel find the fastest way of getting to the other side?
No, the highest speed of sound in an element I see is carbon at 16200 m/sec, far from $3\cdot 10^8$
7h
answered Can a force applied to a wheel find the fastest way of getting to the other side?
1d
answered water pressure in the oceans or great lakes
Apr
10
comment Kepler's third law doesn't give earth's orbital period! Why?
An error of one part in $10^4$ is quite reasonable when one of the inputs has only three digits of accuracy. That is much larger than the planetary perturbations.
Apr
7
revised How to model a rising helium balloon?
correct english
Apr
2
comment What is the maximum range of a bullet flying through the sky?
The fact that the bullet transitions from supersonic to subsonic makes the air resistance very hard to calculate. It becomes a better candidate for experimentation.
Apr
2
comment What is the maximum range of a bullet flying through the sky?
The reason the websites work in vacuum is because it is easy. Two constants ($g$ and initial velocity) and you are done. Air resistance is hard. You need to specify the bullet carefully, but the drag coefficient varies with velocity.
Apr
2
answered How does one estimate the electrical power of a power plant?
Mar
31
awarded  Nice Answer
Mar
30
answered Why is an electron still an elementary particle after absorbing / emitting a photon?
Mar
30
answered Free fall question: Bill shoots his gun
Mar
29
answered What will happen to water at $0^\circ$ Celsius kept in large evacuated chamber
Mar
28
awarded  Nice Answer
Mar
27
revised Why must the particles of an ideal gas be point-like?
add info
Mar
27
revised Confused with how to approach this pulley problem (solved)
correct answer
Mar
27
answered Confused with how to approach this pulley problem (solved)
Mar
27
answered Why must the particles of an ideal gas be point-like?
Mar
27
comment How to calculate the velocity needed for a rocket to get to a L1 point (escape a body without orbiting)?
Your question misses the point that the L1 point is rotating around the earth at the same angular velocity as the moon. Your image is to get to L1 with zero velocity in inertial space, which is a well-defined operation and DavePhD has shown how to calculate the energy requirement for that. However, it is incorrect to think you will just "fall to the moon" from there. The moon is running away from you with its orbital velocity. You have a lot of sideways velocity relative to the moon, so are likely to miss.
Mar
26
answered Light takes too long to get here
Mar
25
comment How do we know that earth is not perfect sphere?
I didn't flag this as not an answer, but precession only shows that the moments around the principal axes are not equal. The earth could be spherical with a nonuniform mass distribution and produce this data.