Uma pedra de gelo a 0*c é colocado em 200g de água à 30*c, num recipiente térmico desprezível e isolado termicamente. o equilíbrio térmico se estabelece em 20*c (dados: valor específico da água c=1.0 cal/g.*c; calor latente de fusão do gelo l=80 cal/g.*c). qual é a massa da pedra de gelo?

Which of the following is a characteristic shared by both electron and light microscopes? a. they both employ the use of objective lenses. b. both microscopes require an internal camera to visualize the specimen. c. both microscopes have a resolving power of 0.01 nm. d. they both utilize white light to magnify the specimen.

The power exerted by a muscle is the product of the force exerted and the velocity of contraction. the area of which of these shaded regions represents the power exerted while a weight is lifted at maximum 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.