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solving crimes with physics
Air resistance is such a powerful force on a moving object that
it can actually affect the distance something travels, even if the
distance is very short. Take, for example, the motion of a base-
ball through air after being hit by a bat. A baseball that would fly
400 feet (122 meters) at sea level with no wind would fly farther at
higher altitudes because it would be affected by factors such as al-
titude, temperature, and relative humidity. Why? At higher altitudes,
the air itself is under less pressure, meaning the molecules are
more spread out than at lower altitudes. Molecules of air at higher
temperatures are also more spread out because the heat energy
that changes the air temperature affects the molecules, and they
move apart from one another. Relative humidity matters because it
is a measure of the number of water droplets in the air in any one
location; try throwing a ball through water sometime. The effect of
increasing altitude is an increase in ball flight of about six feet (1.8
meters) in extra distance for every 1,000 feet (305 meters) of ad-
ditional altitude. Similarly, an increase in temperature of only ten
degrees can add four feet (1.2 meters) to a ball’s flight.
by their huge wings and powerful engines overcomes the force of gravity.
Cars can travel well in excess of 200 miles per hour because of advances in
aerodynamics
and engine design. The power produced by the gas engine
can push the car down the road at high speed even though wind resistance
increases with the increasing speed of the car.
