During the pitching motion, a baseball pitcher exerted an average horizontal force of 60 N against the 0.15 kg baseball while moving it through a horizontal displacement of 2.0 m before he released it.1. How much work did the pitcher do to the baseball as a result of this force?2. Was the work done positive or negative?3. If the baseball's velocity at the start of the pitching action was zero, how fast was the ball moving at the instant of release?4. What would be the time of impact?(Hint: think about impulse-momentum relation from Linear kinetics – the mat exerts an impulseon the pole vaulter, thereby changing his momentum).5. In general, the greater the compression of the mat during impact, the softer the landing (i. e. average force experienced by the jumper will be smaller). However, why might it not be a good idea to have something that compresses too easily?

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.