Math Tools Chapters 9-12
By Ryan Catanese
Directional Measurements
A mile is 5,280 feet while a nautical mile is 6,080 feet. A knot is a measure of speed, one nautical mile per hour. When working with time, rate, and distance problems, make sure to keep the units of measurement the same. Distance = rate x time, Rate = distance / time, and Time = distance / rate.
Speed indicates how fast something is going, while the velocity also indicates the direction. Average speed = distance / time. Acceleration is the rate of change of the speed, acceleration = (ending velocity – starting velocity) / time. In order to determine the ending velocity, (Acceleration x time) + starting velocity = ending velocity.
A g-force is a measure of acceleration, with one “g” represent the force of gravity on the Earth’s surface, or 32.2 feet per second per second. For reference, a kick exerts about 300 g’s on a soccer ball.
Weight and mass are not the same. Mass is a measure of amount wile weight is a measure of the force of gravity pulling on an object. So, mass stays the same regardless of gravity, while the weight changes.
The decibel is a unit of measure for the intensity of sound. One decibel is the softest sound detectable by the human ear, and the ears begin to hurt at 120 dB.
Question: If a boat is traveling at 20 knots, how many miles per hour is that?
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