Question 1

In the process of delivering mail, a postal worker walks 161 m, due east from his truck. He then turns around and walks 194 m, due west from his truck. What is the worker's displacement relative to his truck?

Accepted Answer

The worker's displacement is the net change in position. He walks 161 m east and then 194 m west. The net displacement is 194 m - 161 m = 33 m, due west.

Question 2

A Canadian goose flew 845 km from Southern California to Oregon with an average speed of 28.0 m/s. How long, in hours, did it take the goose to make this journey?

Accepted Answer

To find the time, use the formula: time = distance/speed. Convert 845 km to meters (845,000 m) and divide by 28.0 m/s to get the time in seconds. Then convert seconds to hours: (845,000 m / 28.0 m/s) / 3600 s/h = 8.38 h.

Question 3

A racecar, traveling at constant speed, makes one lap around a circular track of radius r in a time t. Note: The circumference of a circle is given by C=2πr.
-What is the average speed of the car for one complete lap?

Accepted Answer

D

Question 4

Which one of the physical quantities listed below is not correctly paired with its SI unit and dimension?

Accepted Answer

The quantity "luminous flux" is correctly paired with its SI unit, the lumen (lm), but the dimension given is incorrect. The dimension of luminous flux is L^2·J, where L is length and J is luminous intensity. Option D gives the dimension as ML^2T^-3, which is incorrect.

Question 5

A racecar, traveling at constant speed, makes one lap around a circular track of radius r in a time t. Note: The circumference of a circle is given by C=2πr.
-Determine the magnitude of the average velocity of the car for one complete lap.

Accepted Answer

The answer of A racecar, traveling at constant speed, makes...

Question 6

When the outdoor emergency warning siren at Cheryl's school was tested, the sound from the siren took 7.0 s to reach her house located 2.40 km from the school. What is the speed of sound in air?

Accepted Answer

The speed of sound can be calculated using the formula: 
speed = distance/time 
In this case, the distance is 2.40 km (2400 m) and the time is 7.0 s. 
Therefore, the speed of sound in air is: 
speed = 2400 m/7.0 s = 342.86 m/s
Rounded to the nearest ten, the answer is 340 m/s, which corresponds to choice B.

Question 7

A racecar, traveling at constant speed, makes one lap around a circular track of radius r in a time t. Note: The circumference of a circle is given by C=2πr.
-Which one of the following statements concerning this car is true?

Accepted Answer

The average speed of the car is constant because it travels the same distance (the circumference of the track) in the same time (t) for each lap.

Question 8

At time t = 0 s, an object is observed at x = 0 m; and its position along the x axis follows this expression: x = -4t + t², where the units for distance and time are meters and seconds, respectively. What is the object's displacement $\Delta$ x between t = 1.0 s and t = 3.0 s?

Accepted Answer

The displacement is the change in position, so we need to find the difference in position between t = 3.0 s and t = 1.0 s:$$\Delta x = x(3.0 	ext{ s}) - x(1.0 	ext{ s})$$$$= (-4(3.0 	ext{ s}) + (3.0 	ext{ s})^2) - (-4(1.0 	ext{ s}) + (1.0 	ext{ s})^2)$$$$= -12 	ext{ m} + 9 	ext{ m} + 4 	ext{ m} - 1 	ext{ m}$$$$= -16 	ext{ m}$$Therefore, the displacement is -16 m, which is choice A.

Question 9

Alexa's hair grows with an average speed of 3.5 × 10^-⁹m/s. How long does it take her hair to grow 0.30 m? Note: 1 yr = 3.156 × 10⁷s.

Accepted Answer

To find the time, divide the total growth (0.30 m) by the growth rate (3.5 × 10^-9 m/s). Then convert the result from seconds to years using the conversion factor (1 yr = 3.156 × 10^7 s). This calculation gives approximately 2.7 years.

Question 10

A bus leaves New York City, takes a non-direct route and arrives in St. Louis, Missouri 23 hours, 16 minutes later. If the distance between the two cities is 1250 km, what is the magnitude of the bus' average velocity?

Accepted Answer

The magnitude of the average velocity is given by:

average velocity = (total distance traveled) / (total time taken)

Since the bus takes a non-direct route, we have no information about its speed or direction of travel during different parts of the journey. Therefore, we can assume that the bus traveled the entire distance of 1250 km at a constant speed throughout the journey.

The total time taken is given as 23 hours and 16 minutes, which can be converted to hours as:

total time taken = 23 + 16/60 = 23.27 hours

Therefore, the magnitude of the average velocity is:

average velocity = 1250 km / 23.27 hours ≈ 53.7 km/h

So, the best choice is D.

Question 11

A racecar, traveling at constant speed, makes one lap around a circular track of radius r in a time t. Note: The circumference of a circle is given by C=2πr.
-When the car has traveled halfway around the track, what is the magnitude of its displacement from the starting point?

Accepted Answer

The answer of A racecar, traveling at constant speed, makes...

Question 12

Peter noticed a bug crawling along a meter stick and decided to record the bug's position in five-second intervals. After the bug crawled off the meter stick, Peter created the table shown. 
-What is the total distance that the bug traveled between t = 0.00 s and t = 20.0 s? Assume the bug only changed directions at the end of a five-second interval.

Accepted Answer

The bug traveled 7.98 cm in the first 5 seconds, 15.96 cm in the next 5 seconds, 7.98 cm in the next 5 seconds, and 7.98 cm in the last 5 seconds, for a total of 39.9 cm.

Question 13

A particle travels along a curved path between two points P and Q as shown. The displacement of the particle does not depend on

Accepted Answer

The answer of A particle travels along a curved path...

Question 14

A car travels in a straight line covering a total distance of 90.0 miles in 60.0 minutes. Which one of the following statements concerning this situation is necessarily true?

Accepted Answer

The average velocity for the entire trip can be found by dividing the total distance traveled by the time taken to cover that distance.

Average Velocity = Total Distance / Time Taken

= 90.0 miles / 60.0 minutes

= 1.5 miles per minute

To convert this to miles per hour, we can multiply by 60.

Average Velocity = 1.5 miles/min * 60 min/hr

= 90.0 miles per hour

Therefore, the statement that is necessarily true is that the average velocity of the car is 90.0 miles per hour in the direction of motion.

Question 15

During the first 18 minutes of a 1.0-hour trip, a car has an average speed of 11 m/s. What must the average speed of the car be during the last 42 minutes of the trip be if the car is to have an average speed of 21 m/s for the entire trip?

Accepted Answer

The total distance traveled is the same for both the first 18 minutes and the last 42 minutes. Therefore, the average speed for the entire trip is the total distance traveled divided by the total time taken. The total time taken is 18 minutes + 42 minutes = 60 minutes = 1 hour. The total distance traveled is the average speed for the first 18 minutes multiplied by the time taken for the first 18 minutes plus the average speed for the last 42 minutes multiplied by the time taken for the last 42 minutes. Therefore, we have:```Average speed for the entire trip = (Average speed for the first 18 minutes * Time taken for the first 18 minutes + Average speed for the last 42 minutes * Time taken for the last 42 minutes) / Total time taken```Substituting the given values, we get:```21 m/s = (11 m/s * 18 minutes + Average speed for the last 42 minutes * 42 minutes) / 60 minutes```Solving for the average speed for the last 42 minutes, we get:```Average speed for the last 42 minutes = 25 m/s```Therefore, the average speed of the car during the last 42 minutes of the trip must be 25 m/s for the car to have an average speed of 21 m/s for the entire trip.

Question 16

A turtle takes 3.5 minutes to walk 18 m toward the south along a deserted highway. A truck driver stops and picks up the turtle. The driver takes the turtle to a town 1.1 km to the north with an average speed of 12 m/s. What is the magnitude of the average velocity of the turtle for its entire journey?

Accepted Answer

The total displacement is 1082 m north (1100 m - 18 m). The total time is 3.5 minutes (210 seconds) + 91.67 seconds (1100 m / 12 m/s). The average velocity is 1082 m / 301.67 s ≈ 3.6 m/s.

Question 17

For which one of the following situations will the path length equal the magnitude of the displacement?

Accepted Answer

When an object moves in a straight line, the path length is equal to the displacement. However, when an object moves in a curved path or changes direction, the path length is greater than the displacement. In option B, the ball is rolling down an inclined plane, which is a straight line path. Therefore, the path length and displacement will have the same magnitude.

Question 18

Carl Lewis set a world record for the 100.0-m run with a time of 9.86 s. If, after reaching the finish line, Mr. Lewis walked directly back to his starting point in 90.9 s, what is the magnitude of his average velocity for the 200.0 m?

Accepted Answer

The answer of Carl Lewis set a world record for...

Question 19

In which one of the following situations does the car have a westward acceleration?

Accepted Answer

The answer of In which one of the following situations...

Question 20

Peter noticed a bug crawling along a meter stick and decided to record the bug's position in five-second intervals. After the bug crawled off the meter stick, Peter created the table shown. 
-What is the displacement of the bug between t = 0.00 s and t = 20.0 s?

Accepted Answer

Displacement is the change in position of an object. If the bug's final position at t = 20.0 s is 16.1 cm more than its initial position at t = 0.00 s, then the displacement is +16.1 cm.

Quiz 2: Kinematics in One Dimension

In the process of delivering mail, a postal worker walks 161 m, due east from his truck. He then turns around and walks 194 m, due west from his truck. What is the worker's displacement relative to his truck?

A Canadian goose flew 845 km from Southern California to Oregon with an average speed of 28.0 m/s. How long, in hours, did it take the goose to make this journey?

A racecar, traveling at constant speed, makes one lap around a circular track of radius r in a time t. Note: The circumference of a circle is given by C=2πr. -What is the average speed of the car for one complete lap?

Which one of the physical quantities listed below is not correctly paired with its SI unit and dimension?

A racecar, traveling at constant speed, makes one lap around a circular track of radius r in a time t. Note: The circumference of a circle is given by C=2πr. -Determine the magnitude of the average velocity of the car for one complete lap.

When the outdoor emergency warning siren at Cheryl's school was tested, the sound from the siren took 7.0 s to reach her house located 2.40 km from the school. What is the speed of sound in air?

A racecar, traveling at constant speed, makes one lap around a circular track of radius r in a time t. Note: The circumference of a circle is given by C=2πr. -Which one of the following statements concerning this car is true?

At time t = 0 s, an object is observed at x = 0 m; and its position along the x axis follows this expression: x = -4t + t2, where the units for distance and time are meters and seconds, respectively. What is the object's displacement Δ\DeltaΔ x between t = 1.0 s and t = 3.0 s?

Alexa's hair grows with an average speed of 3.5 × 10-9 m/s. How long does it take her hair to grow 0.30 m? Note: 1 yr = 3.156 × 107 s.