A ballet dancer of mass 80 kg and a wingspan of 1m is executing a spin. She then folds her arms and brings them to within 20cm from the central axis of her body. If she was initially making 3 rotations per second, how many does she make now?

Which of the following is implied by the fact that seafloor spreading at the Mid-Atlantic Ridge is causing the Atlantic Ocean to widen by about 5 centimeters a year?

In an ecosystem, producers convert the sun's energy into a usable source for other organisms. Primary consumers eat the producers, secondary consumers eat primary consumers, and tertiary consumers eat secondary consumers.The lion is both a scavenger and a secondary consumer. Thus, they may fill more than one role in the ecosystem.If additional cheetahs were introduced into this ecosystem, shortly thereafter we would expect a decrease in the:

Mr and Mrs Porter drove down to see Sweeney. Mr Porter drove the first 20 km on the way there, and Mrs Porter drove the rest of the way. On the return journey, she drove the first 30 km and he drove the rest. How much farther did Mrs Porter drive than Mr Porter?

Twenty flies are placed in each of four glass tubes. The tubes are sealed. Tubes I and II are partially covered with black paper; Tubes III and IV are not covered. The tubes are placed as shown. Then they are exposed to blue light for five minutes. The number of flies in the uncovered part of each tube is shown in the drawing respond to;

Why is the pupil of the human eye black?

Susan (circle), Ahmad (triangle), and Sam (star) are each walking in an octagonal park on a Sunday morning. At 10:00, the following figure depicts their positions. Susan moves 3 vertices clockwise in each hour, Ahmad moves 1 vertex clockwise each hour, while Sam moves 2 vertices anticlockwise each hour. Will all three ever meet on a vertex at the same instant?