According to NASA, re-entry into the atmosphere occurs at 400,000 feet (122 km). The ship would travel through vacuum for about 68h20min. At this point, it would be travelling at just under 11 km/s. I don't think it will reach anything near terminal velocity before crashing or burning up.
I did...
I'm not a sparky, but couldn't the symbol be a variable capacitor symbol (capacitor with a slash through it, like a variable resistor symbol has a slash through it)? That would fit in with it being a voltage-controlled capacitor.
Edit: I think you're exactly right - I found this diagram with an...
The equation does account for the increase in acceleration as the ship gets closer to earth. The equation with constant acceleration would be much simpler.
The gravitational parameter is a combination of the universal gravitational constant, G, and the mass of the earth. It is a constant and...
If you assume the ship starts with zero velocity and falls directly towards the earth, it forms a radial elliptic trajectory:
http://en.wikipedia.org/wiki/Radial_trajectory#Elliptic_trajectory
You can then use the radial Kepler equation to work out the time for it to fall to the centre of...
Surely this is then just another form of perpetual motion machine? In these cases, violations of the second law are often possible once you ignore friction.
This is an incorrect thought experiment since it confuses internal and external forces. Although you are are applying a torque to twist the rod, it's also apply an equal and opposite torque on you. The overall system, consisting of you and the rod experiences no net change.
If you want a very...
That's a cop-out.
I agree, given the simplifying assumptions that have been made here, it's not possible. But then those calculations can be done on the back of an envelope, using generic data from the internet, in less than 30min.
It is possible to accurately calculate or measure the moments...
It doesn't make this assumption. When you've got bodies that are both spinning about their own axes, as well as rotating about some other axis, the toal angular momentum is the sum of the angular momentum due to the spin, as well as that due to motion about the other axis.
In this example...
The energy gets converted to heat, but angular momentum must still be conserved. The angular momentum of the spinning wheels will be converted to rotation of the truck about it's rotation point. Using some very rough numbers:
Moments of inertia:
I_wheel = 18.4 N.m.s^2
I_truck = 23,263...
This part doesn't really depend on the time system in use. It's only based on seconds because we define c in units of m/s.
If we defined c in untis of m/decimal 'second', the definition would then be the distance travelled by light in a vacuum in 1/c decimal 'seconds'.
Back on the bike after a long, work-induced absence.
21 mile Critical Mass ride through central Johannesburg
http://app.strava.com/activities/20581334
17870
I don't think this is right. Most oxygen in the air is in the form of O2 molecules, which I believe are bigger than water molecules. I think N2 and CO2 molecules may also be bigger.
In most cases, water tight refers to liquid water, not gases or water vapour. I think the actual explanation...
Which is, technically, the correct way of doing it: total distance divided by total time.
I'm not sure about mobile apps, but websites such as Garmin Connect and desktop programs like SportTracks will display both average speed and average moving speed. I think SportTracks also lets you...
I feel it somewhat defeats the purpose of a log if you just add a lump sum, rather than logging each ride individually (although perhaps some flexibility for weekly sums could be allowed).
2x 44mile, this weekend and last weekend.
http://app.strava.com/rides/15251521...
Bear in mind that you may need to extend the ride a little bit to allow some extra time to warm up. I don't think heading straight into intervals is such a good idea - you may end up getting injured.
Intervals are a pretty convenient way to deal with stop streets / lights when ride. Stop at the...
I agree that trainer speed is a poor absolute measure but, provided the trainer isn't completely messed up, it can be a very good relative measure for performance. 25mph on the trainer may be nothing like 25mph on the road, but going from 25mph on that trainer to 27mph is a reasonable indication...
Is there any way you can move the sensor from the front to the back wheel? Speed will give you much more useful information from your trainer than cadence.
Unless you always ride in the same gear, cadence is pretty meaningless. 100rpm in 53-11 is definitely not the same workout as 100rpm in...
Got in a good 31 miles and burned about 1250 kcal with a couple of climbs up a steep ridge in my area. I turned my GPS on about 2000km from where I last turned it off, so it took a while to find the satellites - hence the low distance on Strava: http://app.strava.com/activities/5503589
Total...
They could be. Though looking at Phanuel's http://forums.anandtech.com/showpost.php?p=33069727&postcount=8 graph, they correspond roughly to an hour at 200W for a tempo ride, pushing it to 250-300W for a really hard ride and dropping down to 120W for a light ride.
They also are roughly the...
As others have mentioned, I've found the speed and calorie readings on most spin bikes and gym bikes to be pretty far from what I'd normally expect for rides of various intensities.
I suggest we agree on a simple rule of thumb to apply to rides logged on spinning bikes (and to a lesser extent...
Thermal diffusivity incorporates specific heat, density and thermal conductivity. Specific heat and density are required only for transient solutions. For a steady state solution, only conductivity is required.
Have you seen this?
http://www.ansys.com/staticassets/ANSYS/staticassets/resourcelibrary/article/AA-V4-I2-Bladeless-is-More.pdf
It doesn't have too much detail in the way of calculations, but the velocity contour plot and streamline pictures might be useful.
Here's a comparison of some scales that measure body fat %:
http://www.dcrainmaker.com/2011/08/bod-pod-consumer-scale-comparison-tests_25.html
The seem to be consistent, but not necessarily accurate.
Basic thermodynamics says that it will take less energy and, with a constant heat source, less time to boil room temperature water at higher altitudes.
On the other hand, at higher altitudes, the starting temperature of the water may be lower due to colder ambient conditions. The reduced...
What did the test involve? How long did it last? Did they give any context to the wattage number - was it your power at VO2max, a peak power or the average power for the test? What do you weigh?
Wattage is a measure of the amount of power you produced on the bike. By itself, a number like...
Coasting is freewheeling: you keep on rolling when you're not pedalling.
On a fixed gear bike, the chain is connected directly to the solid rear hub: if you stop pedalling, the rear wheel locks up and you can't keep on rolling.
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