hello quizlet
Home
Subjects
Expert solutions
Create
Study sets, textbooks, questions
Log in
Sign up
Upgrade to remove ads
Only $35.99/year
Physics chapter 1 and 2 study questions
Flashcards
Learn
Test
Match
Flashcards
Learn
Test
Match
Terms in this set (28)
Which of the following would serve as the best time standard?
1. the rotation of Earth upon its axis
2. the vibration of a Cs-133 atom
3. a grandfather clock
4. the buzzing of a mosquito
2. the vibration of a Cs-133 atom
Suppose that you measure the position of a chair using a meter stick and you record the distance of the center of the seat from the wall. Which of the following measurements is the most reasonable?1. 1.043 860 564 2 m
2. 1.043 860 m
3. 1 m
4. 1.04 m
4) 1.04 m
Which of the following statements is correct?
1. If an equation is dimensionally correct it must be true and if it is not dimensionally correct it may be true.
2. If an equation is dimensionally correct it may be true and if an equation is not dimensionally correct it may be true.
3. If an equation is dimensionally correct it may be true and if it is not dimensionally correct then it cannot be true.
4. If an equation is dimensionally correct it must be true and if an equation is not dimensionally correct it cannot be true.
3. If an equation is dimensionally correct it may be true and if it is not dimensionally correct then it cannot be true.
Which of the following expresses 5.2x10-5 s , correctly using the metric prefixes given?
1. 520 ks
2. 0.52 ms
3. 52 μs
4. 52 ns
3) 52 μs
Suppose that two quantities, A and B, have different dimensions. Determine which of the following arithmetic operations could be physically meaningful.
(i) A + B
(ii) A/B
(iii) B − A
(iv) AB
1. (iv) only
2. (ii) only
3. (i) and (iii)
4. (ii) and (iv)
4. (ii) and (iv)
The magnitudes of two vectors are 12 units and 8 units, respectively. What are the largest and smallest possible values for the magnitude of the resultant vector
1. 14.4 and 4
2. 12 and 9
3. 20 and 4
4. None of these.
Answer: 20 and 4
Reasoning: The maximum resultant vector is when the two vectors are parallel, then 12 + 8 = 20. The minimum is when the two vectors are antiparallel, so 12 - 8 = 4.
Let's say that during a thunderstorm you measure the time lag between the flash and the thunderclap to be 3 seconds. If the speed of sound is about 340 m/s, which of the following is the best estimate of your distance to the lightening bolt?
1. about 3 km
2. about 0.3 km
3. about 1 km
4. about 10 km
3) about 1 km
Under which of the following conditions is the magnitude of the average velocity of a particle moving in one dimension smaller than the average speed over the time interval?
1. A particle moves in the +x direction and then reverses the direction of its motion.
2. A particle moves in the −x direction without reversing.
3. There are no conditions for which this is true.
4. A particle moves in the +x direction without reversing.
1. A particle moves in the +x direction and then reverses the direction of its motion.
If a car is traveling eastward and slowing down, what is the direction of the acceleration on the car that causes it to slow down?
1. No acceleration is required to slow the car.
2. eastward
3. westward
4. None of these choices is correct.
3. westward
Which of the following is true?
1. A moving car with constant acceleration can never stop and stay stopped.
2. If a car is traveling eastward, its acceleration is eastward.
3. If a car is slowing down, its acceleration must be negative.
4. If a car is speeding up, its acceleration must be greater than zero.
1. A moving car with constant acceleration can never stop and stay stopped.
The velocity and acceleration of an object
1. must have the same sign.
2. can have opposite signs.
3. must both be zero simultaneously; one cannot be zero and the other nonzero.
4. must have opposite signs.
2. can have opposite signs.
The equations of kinematics, which are given in the table,
1. cannot be used if the acceleration is equal to zero.
2. cannot be used if the acceleration varies with time.
3. can be used in any situation.
4. None of these choices are correct.
2. cannot be used if the acceleration varies with time.
The figure below shows the unusual path of a confused football player. After receiving a kickoff at his own goal, he runs downfield to within inches of a touchdown, then reverses direction and races back until he's tackled at the exact location where he first caught the ball. During this run, which took 25 s, what is the path length he travels?
1. 100 yd
2. 200 yd
3. 0.00 yd
4. It is more than 100 yd, but you must know the exact path to say exactly
Answer: 200 yd
Reasoning: The path length is the total distance the player runs, 200 yd.
What was the player's displacement?
1. 100 yd
2. 200 yd
3. 0.00 yd
4. It is more than 100 yd, but you must know the exact path to say exactly.
Answer: 0.00 yd
Reasoning: The displacement is zero, because the player ends up at his starting position.
During the player's run, which took 25 s, what is his average velocity in the x-direction?
1. 100 yd/s
2. 25.0 yd/s
3. 8.00 yd/s
4. 0.00 yd/s
Answer: 8.00 yd/s
Reasoning: The path length is the total distance the player runs, 200 yd, so the average speed is the path length divided by the total time: 200 yd ¸ 25 s = 8 yd/s.
During the player's run, which took 25 s, what is his average velocity in the x-direction?
1. 100 yd/s
2. 25.0 yd/s
3. 8.00 yd/s
4. 0.00 yd/s
Answer: 0.00 yd/s
Reasoning: The displacement is zero, because the player ends up at his starting position, so the average velocity is also zero.
True or False? A car must always have an acceleration in the same direction as its velocity.
Answer: False
Reasoning: The car may be slowing down, so that the direction of its acceleration is opposite the direction of its velocity.
True or False? It's possible for a slowing car to have a positive acceleration.
Answer: True
Reasoning: If the velocity is in the direction chosen as negative, a positive acceleration causes a decrease in speed.
True or False? It's possible for a slowing car to have a positive acceleration.
Answer: True
Reasoning: If the velocity is in the direction chosen as negative, a positive acceleration causes a decrease in speed.
True or False? An object with constant nonzero acceleration can never stop and remain at rest.
Answer: True
Reasoning: For an accelerating particle to stop at all, the velocity and acceleration must have opposite signs, so that the speed is decreasing. If this is the case, the particle will eventually come to rest. If the acceleration remains constant, however, the particle must begin to move again, opposite to the direction of its original velocity. If the particle comes to rest and then stays at rest, the acceleration has become zero at the moment the motion stops. This is the case for a braking car—the acceleration is negative and goes to zero as the car comes to rest.
A tennis player on serve tosses a ball straight up. While the ball is in free fall, its acceleration
1.increases.
2.decreases.
3.increases and then decreases.
4.decreases and then increases.
5.remains constant.
Answer: remains constant
Reasoning: The acceleration of the ball remains constant while it is in the air. The magnitude of its acceleration is the free-fall acceleration, g = 9.80 m/s2.
As the tennis ball travels through the air, its speed
1.increases.
2.decreases.
3.increases and then decreases.
4.decreases and then increases.
5.remains constant.
Answer: increases and then decreases
Reasoning: As it travels upward, its speed decreases by 9.80 m/s during each second of its motion. When it reaches the peak of its motion, its speed becomes zero. As the ball moves downward, its speed increases by 9.80 m/s each second.
A skydiver jumps out of a hovering helicopter. A few seconds later, another skydiver jumps out, so they both fall along the same vertical line relative to the helicopter. Both skydivers fall with the same acceleration. (Assume g is constant.) The vertical distance between them
1.increases.
2.decreases.
3.stays the same.
Answer: increases
Reasoning: The first jumper will always be moving with a higher velocity than the second. Thus, in a given time interval, the first jumper covers more distance than the second, and the separation distance between them increases.
For the two skydivers, The difference in their velocities
1.increases.
2.decreases.
3.stays the same.
Answer: stays the same
Reasoning: At any given instant of time, the velocities of the jumpers are definitely different, because one had a head start. In a time interval after this instant, however, each jumper increases his or her velocity by the same amount, because they have the same acceleration. Thus, the difference in velocities stays the same.
Michael is going to the store 6 miles away. He rides his bike at 12 mph for the first half of the trip, then walks at 4 mph for the remainder.
Michael's average speed for the trip to the store is closest to:
1. 2 mph
2. 4 mph
3. 6 mph
4. 8 mph
5. 10 mph
6. 12 mph
7. 14 mph
8. exactly halfway between two of the values above
9. impossible to determine
Answer: Possible: (3), (4), (9)
Question A2.01
Discussion:
The average speed is the total distance traveled divided by the total time needed to travel that distance. In this case, we know the total distance is 6 miles, but we do not know the total time.
If you assume that "first half of the trip" means after 3 miles, then it takes Michael 1/4 hour to go the first 3 miles (at 12 mph) and 3/4 hour to go the second 3 miles (at 4 mph), for a total of 1 hour and an average speed of 6 mph.
If you assume that "first half of the trip" means that he spent the same amount of time at each speed, then the average speed is the average of 12 mph and 4 mph, or 8 mph. Let's get this another way: let t be the time needed to complete each half of the trip (in hours). The total distance is therefore (12t + 4t), which must be equal to 6 miles, or 16t = 6. But the average speed is simply the total distance divided by the total time, or 6/(2t) = 3/t = 8 (mph).
Since the meaning of "the first half of the trip" is ambiguous here — does it refer to distance or time? — answers (3), (4), and (9) are all defensible.
Wendy walks 10 m in one direction at 2 m/s, then runs 6 m in the same direction at 6 m/s. Next, she stops for 4 seconds, and finally walks in the opposite direction at 4 m/s for 6 seconds.
Wendy's average speed is closest to:
1. ½ m/s
2. 1 m/s
3. 1½ m/s
4 .2 m/s
5. 2½ m/s
6. 3 m/s
7. 3½ m/s
8. 4 m/s
9. the negative of one of the choices above
10 .impossible to determine
Answer: 3 m/s
Discussion:
The "average speed" of someone is the total distance traveled divided by the total time needed to travel that distance. In this case, Wendy walks 10 m, then runs 6 m, stops briefly, and finally walks 24 m, for a total distance traveled of 40 m. Direction does not matter. It takes Wendy a total of 16 seconds to travel that distance, for an average speed of 2.5 m/s.
Note that you cannot ignore the 4 seconds during which Wendy is not moving. That is still part of her motion.
Ralph walks 3 m to the left in 2 seconds, then 4 m to the right in 3 seconds. Next, he stops for 3 seconds, and finally walks 5 m to the left in 4 seconds.Ralph's final position is closest to:
1. 0 m
2. 2 m
3. 4 m
4. 6 m
5. 8 m
6. 10 m
7. 12 m
8. 14 m
9. The negative of one of the choices above
10. Impossible to determine
Answer: 12 m
Discussion:
The "distance traveled" by someone is not how far the person ends up from his original location, but the total amount of distance covered during the process of moving. If you walk from home to the store and then back again, your "distance traveled" is twice the distance to the store, even though you end up where you started. When driving a car, the distance traveled is the change in odometer reading.
We often call this the "total" distance traveled, just to be clear.
In this case, Ralph walks 3 m, then 4 m, and finally 5 m, for a total of 12 m. Direction does not matter, nor does his starting position.
Ralph walks 3 m to the left in 2 seconds, then 4 m to the right in 3 seconds. Next, he stops for 3 seconds, and finally walks 5 m to the left in 4 seconds.Ralph's displacement is closest to:
left in 4 seconds.Ralph's final position is closest to:
1. 0 m
2. 2 m
3. 4 m
4. 6 m
5. 8 m
6. 10 m
7. 12 m
8. 14 m
9. The negative of one of the choices above
10. Impossible to determine
Answer: Possible (3) and (9)
Discussion:
An object's displacement is the change in its position: final position minus initial position. It has direction associated with it, and does not depend on the path taken between the initial and final points or on the time interval. Mathematically, if x describes an object's position, we represent its displacement as Δx.
Ralph ends up 4 m to the left of his original position, so his displacement is "4 m, left". If the positive direction is chosen to be to the left, then "4 m" (answer 3) is acceptable; if positive is chosen to be to the right, then "-4 m" (answer 9) is acceptable.
Other sets by this creator
Lipid Soluble Vitamins
4 terms
water soluble vitamins
9 terms
Genetics Final
228 terms
Genetics Exam 1 Review
57 terms
Recommended textbook solutions
The Language of Composition: Reading, Writing, Rhetoric
2nd Edition
Lawrence Scanlon, Renee H. Shea, Robin Dissin Aufses
661 solutions
Edge Reading, Writing and Language: Level C
David W. Moore, Deborah Short, Michael W. Smith
304 solutions
Technical Writing for Success
3rd Edition
Darlene Smith-Worthington, Sue Jefferson
468 solutions
Technical Writing for Success
3rd Edition
Darlene Smith-Worthington, Sue Jefferson
468 solutions
Other Quizlet sets
6
407 terms
COMM LAW EXAM 1
18 terms
Casualty guaranteed missed qs
62 terms
FINC 4720 Test 2
28 terms