Question

physics hw (1d motion)

1. in your own words, write what the difference is between distance and displacement?
2. in your own words, write what the difference is between speed and velocity?
3. in your car you have a speedometer. why is it called a speedometer instead of a velocitymeter?
4. i walked 5 miles east, then 3 miles west, then 8 miles east. what is my distance walked? what is my displacement?
5. suzy walked 4 miles west, then 8 miles east, then 2 miles west, then 10 miles east, then 12 miles west. what is suzys distance walked? what is suzys displacement?
6. i ran 3600 meters during a 90 - minute time span. what was my average speed?

Explanation:

Step1: Define distance and displacement concepts

Distance is total path length, displacement is straight - line distance from start to end with direction.

Step2: Answer question 1

Distance is a scalar quantity representing the total length of the path traveled. Displacement is a vector quantity representing the change in position from the starting point to the ending point, including direction.

Step3: Answer question 2

Speed is a scalar quantity that measures how fast an object is moving (rate of change of distance). Velocity is a vector quantity that measures the rate of change of an object's position and includes direction.

Step4: Answer question 3

A speedometer measures speed (a scalar) because it only gives the magnitude of how fast the car is moving (e.g., in miles per hour), without indicating direction.

Step5: Calculate distance in question 4

Distance = 5 + 3+8 = 16 miles.

Step6: Calculate displacement in question 4

Taking east as positive and west as negative, displacement = 5 - 3+8 = 10 miles east.

Step7: Calculate distance in question 5

Distance = 4 + 8+2 + 10+12 = 36 miles.

Step8: Calculate displacement in question 5

Taking east as positive and west as negative, displacement= - 4+8 - 2+10 - 12 = 0 miles.

Step9: Calculate average speed in question 6

Average speed formula is $v=\frac{d}{t}$, where $d = 3600$ m and $t = 90$ min. So, $v=\frac{3600}{90}=40$ m/min.

Answer:

1. Distance is the total path length traveled (scalar), displacement is the change in position with direction (vector).
2. Speed is the rate of change of distance (scalar), velocity is the rate of change of position with direction (vector).
3. It measures only the magnitude of the rate of motion (speed), not direction.
4. Distance: 16 miles; Displacement: 10 miles east.
5. Distance: 36 miles; Displacement: 0 miles.
6. 40 m/min.