Measuring Motion

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Measuring Motion
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Words to Knowspeedmagnitudevelocityaccelerati
on
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All types of motion can be described, measured,
and even predicted.
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Rate of motion can be measured and is called
speed. Velocity is another measure of motion
that takes into consideration both rate of motion
(speed) and direction .
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speed distance/time
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velocity distance/time in a given direction
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So, if speed remains constant, but direction
changes, then the velocity has changed.
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The motion of an object can be described by its
position, direction of motion, and speed.
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We commonly talk about travel in these terms.
For example, last week I left my house (starting
position), went west (direction) on highway 70 at
50 km/hr (speed). I arrived at the beach (ending
position) in 40 minutes.
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But we can really measure ANY motion of any
object at any time by noting its position, speed,
and direction.
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In addition, we can measure changes in an
objects motion and position. We can measure
changing rates of speed (called acceleration) and
we can measure changes in direction.
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Acceleration is the measure of the change in
velocity.
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A race car changes velocity as it goes around
the track. To calculate the acceleration of a
race car, divide the change in velocity by the
time it takes the velocity to change.
acceleration (final velocity - original
velocity) / time ora (v2 v1)/t
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We can apply the concepts of speed and velocity
to enable us to measure time intervals.
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Knowing the relationships of the velocity of
planets, the moon, the earths rotation, etc.
allow us to measure our days, months, years, etc.

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We could also measure time if we know the speed
of a vehicle and the distance traveled.Since
speed distance/time, it follows that time
distance/speed
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What is the difference between speed and
velocity? A only speed is distance traveled
over time B only velocity is distance traveled
over time C both are distance traveled over time
but velocity takes into account direction D both
are distance traveled over time but speed takes
into account direction
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A race car travels 500 km around a track in 3.5
hours. What is the speed of the car? A 143
km/hr B 286 km/hr C 165 km/hr D not enough
information in the question
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An airplane travels 500 km/hour toward the
southwest for 1.3 hours. How far did the plane
go? A 385 hours B 650 km C 650 km/hr
southeast D 385 km
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Which of the following is expressed as
velocity? A 45 km/hr B 45 km/hr southwest C
45 km south D 45 hours
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Which of the following is NOT a way to measure
time intervals? A keeping track of the movement
of the moon B knowing the speed of a vehicle and
how far it traveled C determining velocity from
distance and time D using a computerized
stopwatch
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A race car's beginning velocity is 0 km/sec.
It's velocity at the end of the first lap is 0.06
km/sec. It takes 65 seconds to make the first
lap. What is the race car's acceleration? A
9.23 km/s B 9.23 km/s/s C 39 km/s/s D 39 sec
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A storm becomes a hurricane as it is traveling
at 17mph toward the northwest. It covers 1400
miles before being downgraded to a tropical
storm. How long was the hurricane active? A 82
hours B 8 days C 23,800 hours D 14 days
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A train travels 2500 km in 17 hours. What is the
train's average speed? A 425 km/hr B 147
km/hr C 42.5 km/hr D none of the above
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As you are traveling down main street at 30 mph,
a car passes you going in the same direction.
What can you tell about the car that passed
you A the car was traveling at 33 mph B the
car passing you was going more than 30 mph C the
car passing you was accelerating at a rate of 5
mph/h D nothing - there is not enough
information
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A speed boat is traveling at 65 mph south.
Another is traveling at 65 mph west. What can you
tell about the boats? A they will meet after
traveling 30 minutes B they have the same speed
but not the same velocity C they have the same
velocity but not the same speed D they have the
same acceleration and the same velocity