Question 1

What must be your average speed in order to travel 350 km in 5.15 h?

Accepted Answer

To find the average speed, divide the total distance by the total time: 350 km / 5.15 h = 67.96 km/h, which rounds to 68.0 km/h.

Question 2

A light-year is the distance that light travels in one year. The speed of light is 3.00 × 108 m/s. How many miles are there in one light-year? (1 mi = 1609 m, 1 y = 365 d)

Accepted Answer

C

Question 3

If you run a complete loop around an outdoor track of length 400 m in 100 s, find your
(a) average velocity and (b) average speed.

Accepted Answer

(a) 0 m/s (b) 4 m/s

Question 4

A runner runs around a track consisting of two parallel lines 96 m long connected at the ends by two semicircles with a radius of 49 m. She completes one lap in 100 seconds. What is her average
Velocity?

Accepted Answer

The average velocity of an object moving in a closed loop is 0 m/s because it returns to its starting point, meaning there's no change in position over the time period.

Question 5

You leave on a 549-mi trip in order to attend a meeting that will start 10.8 h after you begin your trip. Along the way you plan to stop for dinner. If the fastest you can safely drive is 65 mi/h, what
Is the longest time you can spend over dinner and still arrive just in time for the meeting?

Accepted Answer

The answer of You leave on a 549-mi trip in...

Question 6

A bat, flying toward the east at 2.0 m/s, emits a shriek that is reflected back to it from a
wall that is 20.0 m in front of the bat at the instant the shriek is emitted. Sound travels at
340 m/s in the air. How many milliseconds after emitting the shriek does the bat hear the
reflected echo from the wall?

Accepted Answer

The answer of A bat, flying toward the east at...

Question 7

An airplane travels at 300 mi/h south for 2.00 h and then at 250 mi/h north for 750 miles. What is the average speed for the trip?

Accepted Answer

The total distance traveled is the sum of the distances in each segment: $2.00 \, \text{h} \times 300 \, \text{mi/h} = 600 \, \text{mi}$ south and $750 \, \text{mi}$ north, for a total of $600 + 750 = 1350 \, \text{mi}$. The time for the first segment is $2.00 \, \text{h}$, and for the second segment, it's $750 \, \text{mi} / 250 \, \text{mi/h} = 3.00 \, \text{h}$, totaling $2.00 + 3.00 = 5.00 \, \text{h}$. The average speed is the total distance divided by the total time: $1350 \, \text{mi} / 5.00 \, \text{h} = 270 \, \text{mi/h}$.

Question 8

A runner ran the marathon (approximately 42.0 km) in 2 hours and 57 min. What was the average speed of the runner in m/s?

Accepted Answer

The total time in seconds is 2 hours * 3600 seconds/hour + 57 minutes * 60 seconds/minute = 7200 seconds + 3420 seconds = 10620 seconds. The average speed in m/s is total distance / total time = 42,000 meters / 10620 seconds = 3.95 m/s.

Question 9

A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100 km/h. What is her average speed for the trip?

Accepted Answer

The total distance is (3.0 h * 80 km/h) + (2.0 h * 100 km/h) = 240 km + 200 km = 440 km. The total time is 3.0 h + 2.0 h = 5.0 h. The average speed is total distance divided by total time: 440 km / 5.0 h = 88 km/h.

Question 10

A polar bear starts at the North Pole. It travels 1.0 km south, then 1.0 km east, and then 1.0 km north to return to its starting point. This trip takes 45 min. What was the bear's average speed?

Accepted Answer

The bear traveled a total distance of 3.0 km (1.0 km south, 1.0 km east, 1.0 km north) in 45 minutes, which is 0.75 hours. Average speed = total distance / total time = 3.0 km / 0.75 h = 4.0 km/h.

Question 11

A motorist travels 160 km at 80 km/h and 160 km at 100 km/h. What is the average speed of the motorist for this trip?

Accepted Answer

The answer of A motorist travels 160 km at 80...

Question 12

A runner runs around a track consisting of two parallel lines 96 m long connected at the ends by two semicircles with a radius of 49 m. She completes one lap in 100 seconds. What is her average
Speed?

Accepted Answer

The total distance of the track is the sum of the lengths of the two parallel lines and the circumferences of the two semicircles. The length of the parallel lines is 2*96 = 192 m. The circumference of a full circle with radius 49 m is 2*π*49, so the total length of the two semicircles is π*49. Therefore, the total distance is 192 + π*49*2 = 192 + 308 = 500 m. The average speed is total distance divided by time, which is 500 m / 100 s = 5.0 m/s.

Question 13

You are driving home on a weekend from school at 55 mi/h for 110 miles. It then starts to snow and you slow to 35 mi/h. You arrive home after driving 4 hours and 15 minutes. How far is your
Hometown from school?

Accepted Answer

The first part of the trip is 110 miles at 55 mi/h, taking 2 hours. The total trip time is 4 hours and 15 minutes (or 4.25 hours). The remaining time is 2.25 hours, during which you travel at 35 mi/h. The distance covered in the snow is 35 mi/h * 2.25 h = 78.75 miles. The total distance is 110 miles + 78.75 miles = 188.75 miles, which rounds to 190 miles.

Question 14

A polar bear starts at the North Pole. It travels 1.0 km south, then 1.0 km east, and then 1.0 km north to return to its starting point. This trip takes 45 min. What was the bear's average velocity?

Accepted Answer

The bear ends up at its starting point, so the displacement is zero. Average velocity is displacement divided by time, and since displacement is zero, the average velocity is 0.00 km/h.

Question 15

If, in the figure, you start from the Bakery, travel to the Cafe, and then to the Art Gallery
(a) what distance you have traveled?
(b) what is your displacement?

Accepted Answer

The answer of If, in the figure, you start from...

Question 16

A race car circles 10 times around a circular 8.0-km track in 20 min. Using SI units
(a) what is its average speed for the ten laps?
(b) what is its average velocity for the ten laps?

Accepted Answer

The answer of A race car circles 10 times around...

Question 17

If, in the figure, you start from the Bakery, travel to the Cafe, and then to the Art Gallery in
2.00 hours, what is your
(a) average speed?
(b) average velocity?

Accepted Answer

The answer of If, in the figure, you start from...

Question 18

If you are driving 72 km/h along a straight road and you look to the side for 4.0 s, how far do you travel during this inattentive period?

Accepted Answer

To find the distance traveled, use the formula: distance = speed × time. Convert the speed from km/h to m/s: 72 km/h = 20 m/s. Then, multiply by the time: 20 m/s × 4 s = 80 m.

Question 19

A motorist makes a trip of 180 miles. For the first 90 miles she drives at a constant speed of 30 mph. At what constant speed must she drive the remaining distance if her average speed for the
Total trip is to be 40 mph?

Accepted Answer

To have an average speed of 40 mph over 180 miles, the total trip time must be 4.5 hours (180 miles / 40 mph). The first 90 miles at 30 mph takes 3 hours. Therefore, the remaining 90 miles must be covered in 1.5 hours, requiring a speed of 60 mph (90 miles / 1.5 hours).

Question 20

An object moves 15.0 m north and then 11.0 m south. Find both the distance it has traveled and the magnitude of its displacement.

Accepted Answer

The total distance traveled is the sum of the individual distances (15.0 m north + 11.0 m south = 26.0 m). The displacement, being a vector quantity, is the net change in position (15.0 m - 11.0 m = 4.0 m to the north).

Quiz 2: Describing Motion: Kinematics in One Dimension

What must be your average speed in order to travel 350 km in 5.15 h?

A light-year is the distance that light travels in one year. The speed of light is 3.00 × 108 m/s. How many miles are there in one light-year? (1 mi = 1609 m, 1 y = 365 d)

If you run a complete loop around an outdoor track of length 400 m in 100 s, find your (a) average velocity and (b) average speed.

A runner runs around a track consisting of two parallel lines 96 m long connected at the ends by two semicircles with a radius of 49 m. She completes one lap in 100 seconds. What is her average Velocity?

You leave on a 549-mi trip in order to attend a meeting that will start 10.8 h after you begin your trip. Along the way you plan to stop for dinner. If the fastest you can safely drive is 65 mi/h, what Is the longest time you can spend over dinner and still arrive just in time for the meeting?

An airplane travels at 300 mi/h south for 2.00 h and then at 250 mi/h north for 750 miles. What is the average speed for the trip?

A runner ran the marathon (approximately 42.0 km) in 2 hours and 57 min. What was the average speed of the runner in m/s?

A motorist travels for 3.0 h at 80 km/h and 2.0 h at 100 km/h. What is her average speed for the trip?

A polar bear starts at the North Pole. It travels 1.0 km south, then 1.0 km east, and then 1.0 km north to return to its starting point. This trip takes 45 min. What was the bear's average speed?

A motorist travels 160 km at 80 km/h and 160 km at 100 km/h. What is the average speed of the motorist for this trip?

A runner runs around a track consisting of two parallel lines 96 m long connected at the ends by two semicircles with a radius of 49 m. She completes one lap in 100 seconds. What is her average Speed?

You are driving home on a weekend from school at 55 mi/h for 110 miles. It then starts to snow and you slow to 35 mi/h. You arrive home after driving 4 hours and 15 minutes. How far is your Hometown from school?

A polar bear starts at the North Pole. It travels 1.0 km south, then 1.0 km east, and then 1.0 km north to return to its starting point. This trip takes 45 min. What was the bear's average velocity?

If, in the figure, you start from the Bakery, travel to the Cafe, and then to the Art Gallery (a) what distance you have traveled? (b) what is your displacement?

A race car circles 10 times around a circular 8.0-km track in 20 min. Using SI units (a) what is its average speed for the ten laps? (b) what is its average velocity for the ten laps?

If, in the figure, you start from the Bakery, travel to the Cafe, and then to the Art Gallery in 2.00 hours, what is your (a) average speed? (b) average velocity?

If you are driving 72 km/h along a straight road and you look to the side for 4.0 s, how far do you travel during this inattentive period?

A motorist makes a trip of 180 miles. For the first 90 miles she drives at a constant speed of 30 mph. At what constant speed must she drive the remaining distance if her average speed for the Total trip is to be 40 mph?

An object moves 15.0 m north and then 11.0 m south. Find both the distance it has traveled and the magnitude of its displacement.