Function example: scope is important
	inside function, only knows about parameters passed and what is inside
	does not see outside variables!



Ball tossed upward, how long is it in flight? what is max height?

define g, initial velocity, t, dt
set initial position as zero (tossed from ground)
initialize max height to zero

while postion > 0
	set acceleration
	update velocity
	update position
	add dt to time elapsed
	is the current height more than the stored maximum?
		if so, current height is now max height
	
now the ball is back on the ground. what is total time, and what was max height?



Adding air resistance

acceleration due to air resistance is -b*v**2 
	v is current velocity, b is a positive constant
	!! always in the direction opposite velocity
	
updating acceleration, with +x upward:
	if v is positive, a = -g - b*v**2
	if v is negative, a = -g + b*v**2
	if v is zero, a = -g
	
	
Finding terminal velocity

new condition: when current velocity - previous velocity is zero (no change in v)

is the absolute value of (v-v_prev) > 0? if so, keep going
initialize v_prev to anything different than initial velocity 
	so that starting value of (v-v_prev) != 0
before updating velocity in the loop, update v_prev = v
then update velocity

How does terminal velocity vary with b?
	for b = 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, make a plot (excel)
	turn this plot in
	
Can you make the terminal velocity thing into a function to make the previous part easier?
	for b in range ... execute function and print result	
	e.g., for i in range(1,10):
		find v terminal
		print it
		b = b + 0.1
		this does it for 10 values of b