Question

facts about speed and velocity
what is important why it is important
speed (pages 332 - 334)

1. define speed.
2. the si units for speed are
3. how is instantaneous speed different from average speed?
4. the equation used for calculating average speed is
5. is the following sentence true or false? you can determine how fast you were going at the mid - point of a trip by calculating average speed for the entire trip.
6. a student walked 1.5 km in 25 minutes, and then, realizing he was late, ran the remaining 0.5 km in 5 minutes. calculate his average speed on the way to school.
7. what type of speed does an automobile’s speedometer display?

graphing motion (page 334)

1. the slope of a line on a distance - time graph represents

physical science guided reading and study workbook • chapter 11

Explanation:

Step1: Define speed

Speed is the rate at which an object moves, measured as the distance traveled per unit of time.

Step2: State SI units of speed

The SI units for speed are meters per second (m/s).

Step3: Differentiate instantaneous and average speed

Instantaneous speed is the speed at a specific instant, while average speed is the total distance traveled divided by the total time taken.

Step4: Write average - speed equation

The equation for calculating average speed is $v = \frac{d}{t}$, where $v$ is average speed, $d$ is total distance, and $t$ is total time.

Step5: Evaluate the statement

False. Average speed for the entire trip gives the overall rate of motion for the whole journey, not the speed at a particular point like the mid - point.

Step6: Calculate average speed

First, find the total distance $d=1.5 + 0.5=2$ km = 2000 m. The total time $t = 25+5 = 30$ minutes = 1800 s. Using the formula $v=\frac{d}{t}$, we have $v=\frac{2000}{1800}=\frac{10}{9}\approx1.11$ m/s.

Step7: Identify speedometer speed

An automobile's speedometer displays instantaneous speed.

Step8: Determine graph slope meaning

The slope of a line on a distance - time graph represents speed.

Answer:

1. Speed is the rate at which an object moves, measured as the distance traveled per unit of time.
2. Meters per second (m/s)
3. Instantaneous speed is the speed at a specific instant, while average speed is the total distance traveled divided by the total time taken.
4. $v=\frac{d}{t}$
5. False
6. $\frac{10}{9}\approx1.11$ m/s
7. Instantaneous speed
8. Speed