kurushio95 said:
2 questions:
What is the terminal velocity of a quarter? and How long does it take a quarter to accelerate to its terminal velocity?
If you do a theoretical calculation for the terminal velocity of a quarter, it'd only be moving at about 30 or 40 mph or so at best if it were falling flat heads or tails up. If that same quarter however was to fall edge side down, it'd be on the move much faster (maybe 100mph or thereabouts absolute tops), since there'd be less area exposed to the 'wind', and hence less air resistance. Because it will spin as it falls, as noted above, it's actual terminal velocity is likely somewhere in between. I once knew some mischievous boys who chucked a penny off the 86th floor of the Empire State Building (I've heard they've since enclosed the balcony), and as far as i know, there were no injuries below or broken windshields or sidewalks. But I think the penny may have bounced off the side of the building on its descent, though, further slowing its fall.
In terms of the time it takes to reach that speed, actually, it never does, but it will approach that speed in probably less than 10 seconds (as also previously noted by Russ.)
Now here's a fun way to determine the approximate terminal velocity of the quarter: Since terminal velocity occurs when the objects weight is equal to the air resistance force, tape a piece of string to a quarter and have a passenger in your car hold it out the window. Then start driving, and the quarter will swing away towards the back. When that angle of swing reaches 45 degrees...bingo! record your constant speed (no acceleration please at time of recording), and you've got the approximate terminal velocity, since at 45 degrees, the wind and weight forces are equal. Drive safely, and do not exceed the posted speed limit. Hmmm, think I'll try that...