Question 1

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 2

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?
A) 2.5 m/s
B) 5.0 m/s
C) 10 m/s
D) 0 m/s
E) 1.3 m/s

Accepted Answer

To find the total distance the runner runs in one lap, we need to add the length of the two straight sections and the length of the two semicircular sections:

Total distance = 2(96 m) + 2(π(49 m)/2) = 192 m + 77π m

Using the formula for average speed (speed = distance/time), we can find the runner's average speed:

Speed = (Total distance)/(Time) = (192 m + 77π m)/100 s ≈ 5.0 m/s

Therefore, the best choice is B, with an average speed of 5.0 m/s.

Question 3

Human reaction times are worsened by alcohol. How much further (in feet) would a drunk driver's car travel before he hits the brakes than a sober driver's car? Assume that both are initially traveling at 50.0 mi/h and their cars have the same acceleration while slowing down, and that the sober driver takes 0.33 s to hit the brakes in a crisis, while the drunk driver takes 1.0 s to do so. (5280 ft = 1 mi)

Accepted Answer

The answer of Human reaction times are worsened by alcohol....

Question 4

Arthur and Betty start walking toward each other when they are 100 m apart. Arthur has a speed of 3.0 m/s and Betty has a speed of 2.0 m/s. How long does it take for them to meet?

Accepted Answer

The answer of Arthur and Betty start walking toward each...

Question 5

An airplane increases its speed at the average rate of 15 m/s². How much time does it take to increase its speed from 100 m/s to 160 m/s? A) 17 s B) 0.058 s C) 4.0 s D) 0.25 s

Accepted Answer

Using the formula for acceleration: 
a = (v2 - v1)/t 
where a is the acceleration, v1 is the initial velocity, v2 is the final velocity, and t is the time. 
We can rearrange the formula to solve for time: 
t = (v2- v1)/a 
Plugging in the values: 
t = (160 m/s - 100 m/s)/(15 m/s^2) 
t = 4.0 s

Question 6

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 7

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?
A) 45 mph
B) 50 mph
C) 52.5 mph
D) 55 mph
E) 60 mph

Accepted Answer

The answer of A motorist makes a trip of 180...

Question 8

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?
A) 0.00 km/h
B) 0.067 km/h
C) 4.0 km/h
D) 5.3 km/h

Accepted Answer

The bear returns to its starting point so the displacement is 0 km. And since its trip took 45 minutes, its velocity is 0 km/h (since velocity is displacement over time).

Question 9

You leave on a 549 - $\text{mi}$  trip in order to attend a meeting that will start $10.8 \mathrm {~h}$ 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?
A) 2.4 h
B) 2.6 h
C) 1.9 h
D) You can't stop at all.

Accepted Answer

To find the longest time you can spend on dinner, first calculate the travel time without stopping: $549 \text{ mi} / 65 \text{ mi/h} = 8.446 \text{ h}$. Subtract this from the total available time: $10.8 \text{ h} - 8.446 \text{ h} = 2.354 \text{ h}$. The closest option is 2.4 h.

Question 10

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) 260 mi/h
B) 270 mi/h
C) 275 mi/h
D) 280 mi/h

Accepted Answer

The total distance traveled is $2 \times 300 + 750 = 1350$ miles. The total time is $2 + \frac{750}{250} = 5$ hours. The average speed is $\frac{1350}{5} = 270$ mi/h.

Question 11

A water rocket can reach a speed of 75 m/s in 0.050 seconds from launch. What is its average acceleration?

Accepted Answer

The answer of A water rocket can reach a speed...

Question 12

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 13

A racquetball strikes a wall with a speed of 30 m/s and rebounds in the opposite direction with a speed of 26 m/s. The collision takes 20 ms. What is the average acceleration of the ball during the collision with the wall? A) 0 m/s² B) 200 m/s² C) 2800 m/s² D) 1500 m/s² E) 1300 m/s²

Accepted Answer

We can use the formula for average acceleration during a collision:

average acceleration = (final velocity - initial velocity) / time

Plugging in the values:

average acceleration = (26 m/s - 30 m/s) / (20 ms) = -2000 m/s^2

The minus sign indicates that the acceleration is in the opposite direction to the initial velocity, which makes sense since the ball rebounds in the opposite direction. However, the question asks for the magnitude of the acceleration, so we need to take the absolute value:

|average acceleration| = 2000 m/s^2

Therefore, the best choice is C, 2800 m/s^2, since it is the closest to 2000 m/s^2.

Question 14

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) 180 mi
B) 190 mi
C) 200 mi
D) 210 mi

Accepted Answer

The answer of You are driving home on a weekend...

Question 15

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?
A) 2.5 m/s
B) 5.0 m/s
C) 10 m/s
D) 0 m/s
E) 1.3 m/s

Accepted Answer

The average velocity is calculated as the displacement divided by the time. Since the runner ends up at the starting point after completing one lap, the displacement is zero. Therefore, the average velocity is 0 m/s.

Question 16

The position x(t) of a particle as a function of time t is given by the equation x(t) = (3.5 m/s)t - (5.0 m/s²)t². What is the average velocity of the particle between t = 0.30 s and t = 0.40 s?

Accepted Answer

The answer of The position x(t) of a particle as...

Question 17

A car is traveling north at $17.7 \mathrm {~m} / \mathrm { s }$ After 12 s its velocity is $14.1 \mathrm {~m} / \mathrm { s }$ in the same direction. Find the magnitude and direction of the car's average acceleration. A) 0.30 m/s², south B) 2.7 m/s², south C) 0.30 m/s², north D) 2.7 m/s², north

Accepted Answer

The answer of A car is traveling north at \(17.7...

Question 18

The captain orders his starship to accelerate from rest at a rate of "1 g" (1 g = 9.8 m/s²). How many days does it take the starship to reach 10% the speed of light? (Light travels at 3.0 × 10⁸ m/s.)

Accepted Answer

The answer of The captain orders his starship to accelerate...

Question 19

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) 85 km/h
B) 88 km/h
C) 90 km/h
D) 92 km/h

Accepted Answer

Average speed = total distance ÷ total time
Let's assume the motorist travels a distance of D.
In the first 3 hours, the motorist travels a distance of 80 x 3 = 240 km.
In the next 2 hours, the motorist travels a distance of 100 x 2 = 200 km.
Therefore, the total distance traveled is 240 + 200 = 440 km.
The total time taken is 3 + 2 = 5 hours.
Therefore, the average speed is 440 ÷ 5 = 88 km/h.

Question 20

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) 84 km/h
B) 89 km/h
C) 90 km/h
D) 91 km/h

Accepted Answer

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

Quiz 2: Motion in One Dimension

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?

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?

Arthur and Betty start walking toward each other when they are 100 m apart. Arthur has a speed of 3.0 m/s and Betty has a speed of 2.0 m/s. How long does it take for them to meet?

An airplane increases its speed at the average rate of 15 m/s2. How much time does it take to increase its speed from 100 m/s to 160 m/s?

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?

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?

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?

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 water rocket can reach a speed of 75 m/s in 0.050 seconds from launch. What is its average acceleration?

A racquetball strikes a wall with a speed of 30 m/s and rebounds in the opposite direction with a speed of 26 m/s. The collision takes 20 ms. What is the average acceleration of the ball during the collision with the wall?

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 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?

The position x(t) of a particle as a function of time t is given by the equation x(t) = (3.5 m/s)t - (5.0 m/s2)t2. What is the average velocity of the particle between t = 0.30 s and t = 0.40 s?

A car is traveling north at 17.7 m/s17.7 \mathrm {~m} / \mathrm { s }17.7 m/s After 12 s its velocity is 14.1 m/s14.1 \mathrm {~m} / \mathrm { s }14.1 m/s in the same direction. Find the magnitude and direction of the car's average acceleration.

The captain orders his starship to accelerate from rest at a rate of "1 g" (1 g = 9.8 m/s2). How many days does it take the starship to reach 10% the speed of light? (Light travels at 3.0 × 108 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 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?

An airplane increases its speed at the average rate of 15 m/s². How much time does it take to increase its speed from 100 m/s to 160 m/s?

The position x(t) of a particle as a function of time t is given by the equation x(t) = (3.5 m/s)t - (5.0 m/s²)t². What is the average velocity of the particle between t = 0.30 s and t = 0.40 s?

A car is traveling north at $17.7 \mathrm {~m} / \mathrm { s }$ After 12 s its velocity is $14.1 \mathrm {~m} / \mathrm { s }$ in the same direction. Find the magnitude and direction of the car's average acceleration.

The captain orders his starship to accelerate from rest at a rate of "1 g" (1 g = 9.8 m/s²). How many days does it take the starship to reach 10% the speed of light? (Light travels at 3.0 × 10⁸ m/s.)