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 Mar 20 comment Rocket propelled by a giant monochromatic laser From answers.yahoo.com/question/index?qid=20100521204409AAk1lkq, $m_{photon} = \frac {h*f} {c^2}$? Seems bizarre, and the conservation of momentum could be used to calculate it. How do you account for the Tsiolkovski Rocket Equation, based on the (rest) mass and velocity of the exhaust? Does it not apply in this situation? Mar 20 comment How to calculate the velocity needed for a rocket to get to a L1 point (escape a body without orbiting)? I think you're thinking of an orbital insertion; in my case I don't want or need any additional 'horizontal' velocity; unless it can be used to increase the vertical. I just want to reach the highest point I can. Mar 20 comment How to calculate the velocity needed for a rocket to get to a L1 point (escape a body without orbiting)? Wouldn't launching off-normal (straight up) 'add velocity' at the expense of some altitude? What angle would maximize altitude from Earth's surface? Mar 20 comment Would it be economical to add a counterweight to rocket launches? Example: Take a fully loaded Saturn V rocket at 2,800,000kg, and add a counterweight that will reduce its effective weight for the first 10 seconds to 400,000kg and detach. It burns 2,100,000kg of fuel in the first stage in 161s, so 13,000kg/s of fuel is lost. Without the counterweight, the first 10 seconds would net a $\Delta v = 4,440m/s*\ln(2,800,000/2,670,000) = 211m/s$. With the counterweight: $\Delta v = 4,440m/s*\ln(400,000/270,000) = 1745 m/s$, or roughly Mach 5.1. Mar 19 comment Would it be economical to add a counterweight to rocket launches? I should add that I wasn't counting on the acceleration from the counterweights to be of much importance in and of themselves; the 63 m/s velocity difference would pale in comparison (I think) to how fast the onboard rocket engines could accelerate the lessened (or non-zero) effective mass. Is there a way to calculate this? Mar 19 asked How to calculate the velocity needed for a rocket to get to a L1 point (escape a body without orbiting)? Mar 19 answered Rocket propelled by a giant monochromatic laser Jan 28 comment Could the Heisenberg Uncertainty Principle turn out to be false? The Heisenberg Uncertainty Principle is an unfalsifiable claim? All of (good) science is falsifiable. See the first paragraph: en.wikipedia.org/wiki/Falsifiability Jan 13 awarded Popular Question Dec 15 awarded Popular Question Dec 8 awarded Notable Question Oct 28 awarded Nice Question Jun 25 accepted Could we make a trebuchet that could launch objects to a stable orbit? Jun 25 comment Would it be economical to add a counterweight to rocket launches? How about four steel cables, each holding 100 tons? Some bridge reinforcement cables are rated for more than this. Jun 25 comment Would it be economical to add a counterweight to rocket launches? Further, I do refer to wikipedia. Since you seem to be of the opinion that this has been answered therein, could you provide a wikipedia link that properly addresses this question? Jun 25 comment Would it be economical to add a counterweight to rocket launches? I'm aware the total energy would be the same, but lifting the counterweights could be powered by renewable resources like wind and solar, reduce the amount of fuel carried to start acceleration and thus lowering the weight and thus further reducing fuel (the Tsiolkovsky rocket equation), and could perhaps be economical across multiple launches. Jun 25 accepted Are there any other mechanisms that can make virtual particles 'real' other than Hawking Radiation and Universe Births? Jun 25 accepted What is the general formula for a trebuchet? Jun 25 accepted What is the most efficient machine for translating gravitational potential energy of one mass into kinetic energy of a different mass? Jun 25 accepted Lever Mechanics - How to formulate an ideal lever launch