B: Physics = Changes in Motion 1.1 Average Speed

Question 1

What is average speed?

Answer 1

Average speed is equal to the total distance travelled divided by the elapsed time.

Average speed formula: average speed = total distance / elapsed time.

Question 2

How does average speed affect elapsed time?

Answer 2

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.

Question 3

Fill in the blank: Average speed is calculated as total distance divided by _______.

Answer 3

elapsed time

This formula is fundamental in understanding motion in different transportation modes.

Question 4

True or False: Average speed is the same for all modes of transportation over the same distance.

Answer 4

False

Different modes of transportation can have different average speeds, affecting the time taken to travel the same distance.

Question 5

What is uniform motion?

Answer 5

Motion in a straight line at a constant speed

Uniform motion is characterized by a straight line on a distance-time graph.

Question 6

What is non-uniform motion?

Answer 6

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.

Question 7

In the context of transportation, which mode typically demonstrates uniform motion?

Answer 7

Car on cruise control

The graph shows that the car produced a straight line, indicating uniform motion.

Question 8

Is uniform motion common in the natural world?

Answer 8

No, it is rare

Most objects in the natural world experience changes in speed or direction.

Question 9

Fill in the blank: Uniform motion is characterized by _______.

Answer 9

motion in a straight line at a constant speed

Question 10

Fill in the blank: Non-uniform motion involves _______.

Answer 10

a change in speed, direction, or both

Question 11

What is instantaneous speed?

Answer 11

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.

Question 12

What is an example of a technology that can move with uniform motion?

Answer 12

A car on cruise control travelling on a straight, level section of highway

This example illustrates uniform motion, where the speed remains constant.

Question 13

What do speed limit signs indicate?

Answer 13

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.

Question 14

What should drivers do when conditions are not ideal?

Answer 14

Reduce their speeds

Drivers are expected to adjust their speed according to road conditions for safety.

Question 15

What is a scalar quantity?

Answer 15

A quantity consisting of magnitude only, not direction

Scalar quantities are defined by their size or amount, without any consideration of direction.

Question 16

True or False: Speed limits refer to the maximum average speed of a vehicle.

Answer 16

False

Speed limits refer specifically to the maximum instantaneous speed.

Question 17

Fill in the blank: A speed limit sign does not show which way you are _______.

Answer 17

travelling

The speed limit only provides information about the allowed speed, not the direction of travel.

Question 18

What might drivers argue when receiving a speeding ticket?

Answer 18

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.

Question 19

What do highway signs in Canada typically display for distances and speeds?

Answer 19

Distances in kilometres and speeds in kilometres per hour (km/h)

Highway signs often omit units due to readability concerns while driving.

Question 20

Why do highway signs often leave out details like units?

Answer 20

To limit the amount of information drivers can safely read while driving

There is also a size limit on the signs.

Question 21

What is the average speed of an owl that drops 1.30 m in 0.80 s in metres per second?

Answer 21

1.625 m/s

The average speed is calculated by dividing the distance by the time.

Question 22

Fill in the blank: Highway signs that display scalar quantities often don’t include _______.

Answer 22

units

Question 23

What is the formula to determine average speed?

Answer 23

Average speed = Distance / Time

This formula is fundamental for solving problems involving motion.

Question 24

True or False: In Canada, it is always necessary for highway signs to display units of measurement.

Answer 24

False

It is understood that distances are in kilometres and speeds are in km/h unless stated otherwise.

Question 25

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).

Answer 25

5.85 km/h

This conversion is done by multiplying the speed in m/s by 3.6.

Question 26

What is the rule regarding significant digits when rounding answers?

Answer 26

The answer must be rounded to the least number of significant digits in the measurements used in the calculation.

Question 27

If a distance measurement has three significant digits and time has two significant digits, how should the final answer be rounded?

Answer 27

To two significant digits.

Question 28

What is the formula to calculate average speed?

Answer 28

Average speed = Distance / Time

Question 29

To find David’s average speed in kilometres per hour, what values do you need?

Answer 29

Distance of 20.5 km and time of 2.5 h.