A beach ball and a bowling ball were sitting on a shelf. Someone bumped the shelf and the bowling ball and beach ball rolled off the shelf at the same time. They both hit the ground at the same
time and had the same speed.
Which of these statements correctly compares the kinetic energy
of the two objects just before they hit the ground?

A The bowling ball had more kinetic energy because it
had less potential energy when it was on the shelf.
B The bowling ball had more kinetic energy because it
has more mass.
C Both balls had the same kinetic energy because they
had the same speed.
D Both balls had the same kinetic energy because they had the same potential energy when they were on the
shelf.

A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.