Download 1.0 SPEED - Intro handout v4 - Completed

SPH3U - Kinematics
INTRO TO SPEED
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Where, v = speed,
Ad = distance, and
At = time interval
Example: How long does It take a car to travel 46 m when its average speed is 60.0 m/s?
^ A
A1
X
L
Definition
Average Speed
(Vavg)
VSJ? = Total distance
Total time
Example
A City of Markham bus took 1.0 hours to
travel 60.0 km. Vavg = JMMiL = fj* X*//
}.
Instantaneous
Speed (Vm5t)
Constant Speed
An object's speed at an instant in
time
The reading on a car's speedometer
Speed does not change
Car on cruise control on a flat road
a situation when...
^
SPH3U Physics
Unit: Kinematics
Problem Solving with Uniform Motion
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*Definition of "uniform motion" (which you will be expected to know): Uniform
motion means constant speed AND direction.
Text reference for this concept: p. 14-15, "Average Speed" description and example.
Practice Questions:
1. If a car travels 485 m in 13 seconds, what was the car's average speed? [ans 37m/s]
2. A SCUBA diver rides an underwater tricycle at an average speed of 1.74 km/h for 60,0 h.
What distance do they travel in this time? [ans 104 km]
3. A truck driver, reacting quickly to an emergency, applies the brakes. During the driver’s
0.32s reaction time, the truck maintains a constant velocity of 27 m/s [FWD]. What distance
did the truck move during the time the driver takes to react? [8.6 m]
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4. An airplane is travelling from Vancouver to Toronto following the jet stream. The plane
cruised at an average speed of 1.10
km/h for the 4.00 x 103 km flight. How long did
the flight take? If the plane left Vancouver at 3:00 am EST, what time did it arrive in
Toronto? [3.6 h; 6:36am] (*lf you can't figure out the answer 6:38am, take your time and try
again.)
5. A swimmer crosses a circular pool with a radius of 16 m in 21 s.
a) What is the swimmer's average speed? [1.5 m/s]
b) If the swimmer were to swim around the circumference of the pool at this same
speed, how long would it take? [66 s]
6. OPTIONAL (Challenge question): Two sprinters are racing. Billy has a head start of 3.0 s and
is travelling at 8 m/s. Biff travels at 10 m/s. If the race is 200m, who would win? By how
much? [Biff wins by 2.0 s]
!