Il a shooting star is actually the track of a meteor, typically a small chunk of debris from a comet that has entered the earth's atmosphere. as the drag force slows the meteor down, its kinetic energy is converted to thermal energy, leaving a glowing trail across the sky. a typical meteor has a surprisingly small mass, but what it lacks in size it makes up for in speed. assume that a meteor has a mass of 1.5 g and is moving at an impressive 50 km/s, both typical values. what power is generated if the meteor slows down over a typical 2.1 s? can you see how this tiny object can make a glowing trail that can be seen hundreds of kilometers away? 61. a. how much work does an elevator motor do to lift a 1000 kg elevator a height of 100 m at a constant speed? b. how much power must the motor supply to do this in 50 s at constant speed?

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.