What tool is used to measure air pressure?

Acurve connects the data points that are plotted. (physical science chapter 11 motion)

You notice a very one-dimensional-thinking snail crawling along one rail of a railroad track. naturally, you remove it to a safer place. but before you do, you observe it as it moves from position xi = -92.9 cm to position xf = -64.9 cm along the rail, as measured from a point where one rail abuts the next. what is the snail\'s displacement δx in centimeters?

Gunpowder residue is most likely to show up where on a shooters hands