Apassive solar home has energy stored in a concrete floor of 1000 square feet. how thick should this floor be to store 15 btu with a temperature swing of 20 degrees f? (compute the answer in feet. if the floor should be one tenth of a foot thick, enter 0.1) (note: you'll need to find a value in your textbook for the energy storage capacity of concrete)

Consider two less-than-desirable options. in the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. in the second option you are driving 30 mph and crash head-on into a stationary brick wall. in neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. which of these two situations would result in the greatest impact force?