1. the self-diffusion coefficient of h2o molecules in water is 2.26 x 10-5 cm2 s-1 at 25 oc. estimate how long it takes for an h2o molecule in water to travel: a. 1.0 cm at 25 oc b. 2.0 cm at 25 oc c. 2.0 cm at 50 oc (this one will take some creativity…) hint: the argument in the error function relationship for fick's second law [x/(2*(dt)^.5] must be a constant since the error function is constant, therefore: x = k' 2 (dt)0.5 where x is the diffusion distance and t is time and d is the diffusion constant. we can just assume k' =1 which is not actually the case but at least can us get order of magnitude estimates for diffusion distances.

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)

the answer is c. the lower legs are levers, and the knees are fulcrums. the ankles hold the loads.

the speed of the cart after 3 seconds of low fan speed is ⇒ 54.0 cm/s.

the speed of the cart after 5 seconds of medium fan speed is ⇒ 120.0 cm/s.

the speed of the cart after 2 seconds of high fan speed is ⇒ 64.0 cm/s. 

just did the lab.