B: Physics = Changes in Motion 1.1 Average Speed Flashcards
What is average speed?
Average speed is equal to the total distance travelled divided by the elapsed time.
Average speed formula: average speed = total distance / elapsed time.
How does average speed affect elapsed time?
Different modes of transportation have the same distance but different average speeds, leading to varying elapsed times.
This illustrates that even with the same distance, the time taken can differ significantly based on the speed.
Fill in the blank: Average speed is calculated as total distance divided by _______.
elapsed time
This formula is fundamental in understanding motion in different transportation modes.
True or False: Average speed is the same for all modes of transportation over the same distance.
False
Different modes of transportation can have different average speeds, affecting the time taken to travel the same distance.
What is uniform motion?
Motion in a straight line at a constant speed
Uniform motion is characterized by a straight line on a distance-time graph.
What is non-uniform motion?
Motion with a change in speed, direction, or both
Non-uniform motion is illustrated by changes in speed or direction in various modes of transportation.
In the context of transportation, which mode typically demonstrates uniform motion?
Car on cruise control
The graph shows that the car produced a straight line, indicating uniform motion.
Is uniform motion common in the natural world?
No, it is rare
Most objects in the natural world experience changes in speed or direction.
Fill in the blank: Uniform motion is characterized by _______.
motion in a straight line at a constant speed
Fill in the blank: Non-uniform motion involves _______.
a change in speed, direction, or both
What is instantaneous speed?
Speed at an instant of time
Instantaneous speed refers to the speed of an object at a specific moment, as opposed to average speed over a period of time.
What is an example of a technology that can move with uniform motion?
A car on cruise control travelling on a straight, level section of highway
This example illustrates uniform motion, where the speed remains constant.
What do speed limit signs indicate?
The maximum speed permitted at any moment along a roadway
Speed limits are set for ideal conditions and refer to instantaneous speed, not average speed.
What should drivers do when conditions are not ideal?
Reduce their speeds
Drivers are expected to adjust their speed according to road conditions for safety.
What is a scalar quantity?
A quantity consisting of magnitude only, not direction
Scalar quantities are defined by their size or amount, without any consideration of direction.
True or False: Speed limits refer to the maximum average speed of a vehicle.
False
Speed limits refer specifically to the maximum instantaneous speed.
Fill in the blank: A speed limit sign does not show which way you are _______.
travelling
The speed limit only provides information about the allowed speed, not the direction of travel.
What might drivers argue when receiving a speeding ticket?
That they were travelling under the posted speed limit for most of their trip
This argument is irrelevant if they exceeded the speed limit at any monitored moment.
What do highway signs in Canada typically display for distances and speeds?
Distances in kilometres and speeds in kilometres per hour (km/h)
Highway signs often omit units due to readability concerns while driving.
Why do highway signs often leave out details like units?
To limit the amount of information drivers can safely read while driving
There is also a size limit on the signs.
What is the average speed of an owl that drops 1.30 m in 0.80 s in metres per second?
1.625 m/s
The average speed is calculated by dividing the distance by the time.
Fill in the blank: Highway signs that display scalar quantities often don’t include _______.
units
What is the formula to determine average speed?
Average speed = Distance / Time
This formula is fundamental for solving problems involving motion.
True or False: In Canada, it is always necessary for highway signs to display units of measurement.
False
It is understood that distances are in kilometres and speeds are in km/h unless stated otherwise.
Calculate the average speed of the owl in kilometres per hour (km/h) given its average speed in metres per second (1.625 m/s).
5.85 km/h
This conversion is done by multiplying the speed in m/s by 3.6.
What is the rule regarding significant digits when rounding answers?
The answer must be rounded to the least number of significant digits in the measurements used in the calculation.
If a distance measurement has three significant digits and time has two significant digits, how should the final answer be rounded?
To two significant digits.
What is the formula to calculate average speed?
Average speed = Distance / Time
To find David’s average speed in kilometres per hour, what values do you need?
Distance of 20.5 km and time of 2.5 h.
