Whale blubber was once used by many countries to make lamp oil and other products. Because of the usefulness of whale blubber, huge numbers of whales were caught and killed in the 1800s. As a result, the whale populations around the world severely dropped. In the late 1800s, electric lights were introduced in many cities. How do you think the use of electric lights affected whale populations?
A.
Most whale populations began to rise.
B.
Most whale populations became extinct.
C.
Most whale populations moved to other areas.
D.
Most whale populations continued to decline.

Water is siphoned from a large tank and discharges into the atmosphere through a 50-mm diameter tube. the end of the tube is b = 2.6 m below the tank bottom which is a = 6.7 m deep, and viscous effects are negligible. determine the maximum height h over which the water can be siphoned without cavitation occurring. atmospheric pressure is 101.4 kpa, and the water vapor pressure is 1.79 kpa (absolute). report your answer in meters to two decimal places.

Researchers conducted an experiment to identify the effects of three different hand sanitizers on the growth of bacteria. the researchers grew one type of bacteria in twenty-four identical covered petri dishes. then, they opened eighteen petri dishes and applied the three hand sanitizers to six petri dishes each. they left the remaining six petri dishes closed as a control group. when the researchers measured the growth of bacteria two days later, the six dishes that had no hand sanitizer showed the least amount of bacterial growth. the researchers concluded that not using any hand sanitizer would lead to the least bacterial growth. which statement best explains why the researchers’ conclusion was not justified? the experiment tested too many variables. the control group was not treated the same as the experimental group. the sample size of twenty-four petri dishes is not large enough. the single type of bacteria is not adequate to make any conclusions.

How can you measure the amplitude of a longitudinal wave?