This is Your Brain Without Gravity

What happens to your brain when you have no sense of up? Researchers are scanning the brains of astronauts to track just how badly space messes with our ability to think.

Source: This is Your Brain Without Gravity

There’s an increasing amount of data from studies that suggest we simply aren’t made for interstellar travel.  Organs can reorientate themselves, ability to concentrate is compromised, spinal issues…

How the ISS Astronauts Grew Their Space Lettuce

Interesting to see what microgravity teaches us about agriculture!

Don’t know why they use the word “microgravity”?  If it’s in orbit, the effects of gravity have to be zero by definition… Because there is no such thing as “zero gravity”!  There’s gravity from the sun all the way out here, it’s really more like no relative acceleration.  As in microgravity, you’re actually in perpetual free fall.

Two Cyclists, Weighing 50 and 100 Kg each, Ride up a Hill – Heavier Does More Work?

Assume the cyclists are on identical bikes, and their frontal profile is identical (which is obviously unlikely but it makes life easier) so air resistance is not a factor.  Two Cyclists, One Hill… 😉

Will the 100 Kg rider have done exactly twice the work of the 50 Kg rider? Logic suggests that the potential energy of the 100 Kg rider should be double that of the 50 Kg rider. If both riders were running a power meter (be it in the hub, cranks, or pedals) well that show double the work having been done?  And what is the appropriate measurement for that? Watt hours?

Answer

Yes, the 100 Kg cyclist (accounting for bike weight, clothing, helmet, etc) performs twice the work against gravity, IE: raised their gravitational potential energy twice as much (W = mgh). But the heavier cyclist would effectively do more work, having to work against friction and drag. They also expend more energy pedaling as he has heavier legs.  Leg weight doesn’t work against gravity, but the mechanics of pedaling does require you to overcome inertia (proportional to mass).

You can measure work (and heat and energy) in many ways. Joule, Newton meters, Watt hours, Coulomb Volts etc. With mechanical work, such as cyclists riding up a hill, Newton meters or Joule(s).  But those with power meters talk in watts.