This document contains multiple physics problems involving concepts like kinematics, forces, gravity, and projectile motion. The problems involve calculating values like displacement, velocity, acceleration, and time for objects moving with constant or changing speed in one or two dimensions. The document tests understanding of equations of motion and how to apply concepts like initial velocity, acceleration, displacement, and time intervals to solve for unknown values.
1. 1.1/3 points | Previous AnswersSerPSE8 2.P.010.My Notes |
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Points
Submissions Used
A car travels along a straight line at a constant speed of 41.5
mi/h for a
distance d and then another distance d in the same direction at
another constant
speed. The average velocity for the entire trip is 25.0 mi/h.
(a) What is the constant speed with which the car moved during
the second
distance d?
Your response is within 10% of the correct value. This may be
due to roundoff
error, or you could have a mistake in your calculation. Carry out
2. all intermediate
results to at least four-digit accuracy to minimize roundoff
error. mi/h
(b) Suppose the second distance d were traveled in the opposite
direction; you
forgot something and had to return home at the same constant
speed as found
in part (a). What is the average velocity for this trip?
Your response differs significantly from the correct answer.
Rework your solution
from the beginning and check each step carefully. mi/h
(c) What is the average speed for this new trip?
mi/h
2.–/3 pointsSerPSE8 2.P.013.My Notes |
Question Part
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3. Submissions Used
A velocity—time graph for an object moving along the x axis is
shown in the
figure. Every division along the vertical axis corresponds to
2.00 m/s and each
division along the horizontal axis corresponds to 2.50 s.
(a) Plot a graph of the acceleration versus time.
This answer has not been graded yet.
(b) Determine the average acceleration of the object in the
following time
interval t = 12.5 s to t = 37.5 s. m/s2
(c) Determine the average acceleration of the object in the
following time
interval t = 0 to t = 50.0 s.
m/s2
4. 3.–/3 pointsSerPSE8 2.P.016.WI.My Notes |
A particle starts from rest and accelerates as shown in the figure
below.
(a) Determine the particle's speed at t = 10.0 s.
m/s
Determine the particle's speed at t = 20.0 s?
m/s
(b) Determine the distance traveled in the first 20.0 s. (Enter
your answer to one
decimal places.)
m
4.–/3 pointsSerPSE8 2.P.017.MI.My Notes |
A particle moves along the x axis according to the equation
x = 1.99 + 2.99t − 1.00t2,
where x is in meters and t is in seconds.
(a) Find the position of the particle at t = 2.50 s.
m
5. (b) Find its velocity at t = 2.50 s.
m/s
(c) Find its acceleration at t = 2.50 s.
m/s2
5.–/2 pointsSerPSE8 2.P.020.My Notes |
Draw motion diagrams for the following items. (Do this on
paper. Your instructor
may ask you to turn in your work.)
(a) an object moving to the right at constant speed
(b) an object moving to the right and speeding up at a constant
rate
(c) an object moving to the right and slowing down at a constant
rate
(d) an object moving to the left and speeding up at a constant
rate
(e) an object moving to the left and slowing down at a constant
rate
This answer has not been graded yet.
6. (f) How would your drawings change if the changes in speed
were not uniform;
that is, if the speed were not changing at a constant rate?
This answer has not been graded yet.
6.–/5 pointsSerPSE8 2.P.021.My Notes |
A parcel of air moving in a straight tube with a constant
acceleration of -
4.10 m/s2 and has a velocity of 13.5 m/s at 10:05:00 a.m.
(a) What is its velocity at 10:05:01 a.m.?
m/s
(b) What is its velocity at 10:05:04 a.m.?
m/s
(c) What is its velocity at 10:04:59 a.m.?
m/s
(d) Describe the shape of a graph of velocity versus time for
this parcel of air.
7. This answer has not been graded yet.
(e) Argue for or against the following statement: "Knowing the
single value of an
object's constant acceleration is like knowing a whole list of
values for its
velocity."
This answer has not been graded yet.
7.–/3 pointsSerPSE8 2.P.024.MI.My Notes |
We investigated a jet landing on an aircraft carrier. In a later
maneuver, the jet
comes in for a landing on solid ground with a speed of 95 m/s,
and its
acceleration can have a maximum magnitude of 5.52 m/s2 as it
comes to rest.
(a) From the instant the jet touches the runway, what is the
minimum time
interval needed before it can come to rest?
s
8. (b) Can this jet land on a small tropical island airport where the
runway is 0.800
km long?
Yes No
(c) Explain your answer.
This answer has not been graded yet.
8.3/5 points | Previous AnswersSerPSE8 2.P.027.My Notes |
A speedboat travels in a straight line and increases in speed
uniformly
from vi = 12.5 m/s to vf = 41.5 m/s in a displacement Δx of 150
m. We wish to
find the time interval required for the boat to move through this
displacement.
(a) Draw a coordinate system for this situation. (Do this on
paper. Your
instructor may ask you to turn in this work.)
(b) What analysis model is most appropriate for describing this
9. situation?
particle under constant speed particle under constant
acceleration particle in
equilibrium
(c) From the analysis model, what equation is most appropriate
for finding the
acceleration of the speedboat?
vf = vi + at
Δx = vi +
1
2
at2
vf2 = vi2 + 2aΔx
(d) Solve the equation selected in part (c) symbolically for the
boat's
acceleration in terms of vi, vf, and Δx.
a =
10. (e) Substitute numerical values to obtain the acceleration
numerically.
m/s2
(f) Find the time interval mentioned above.
s
9.1/4 points | Previous AnswersSerPSE8 2.P.033.My Notes |
An object moves with constant acceleration 4.10 m/s2 and over
a time interval
reaches a final velocity of 12.8 m/s.
(a) If its initial velocity is 6.4 m/s, what is its displacement
during the time
interval?
m
(b) What is the distance it travels during this interval?
m
(c) If its initial velocity is -6.4 m/s, what is its displacement
during the time
11. interval?
Your response differs from the correct answer by more than
10%. Double check
your calculations. m
(d) What is the total distance it travels during the interval in
part (c)?
Your response differs from the correct answer by more than
10%. Double check
your calculations. m
10.–/4 pointsSerPSE8 2.P.038.My Notes |
An attacker at the base of a castle wall 3.90 m high throws a
rock straight up
with speed 9.00 m/s from a height of 1.70 m above the ground.
(a) Will the rock reach the top of the wall?
Yes No
(b) If so, what is its speed at the top? If not, what initial speed
12. must it have to
reach the top?
m/s
(c) Find the change in speed of a rock thrown straight down
from the top of the
wall at an initial speed of 9.00 m/s and moving between the
same two points.
m/s
(d) Does the change in speed of the downward-moving rock
agree with the
magnitude of the speed change of the rock moving upward
between the same
elevations? Explain physically why it does or does not agree.
This answer has not been graded yet.
11.0/1 points | Previous AnswersSerPSE8 2.P.041.WI.My Notes
|
A ball is thrown directly downward with an initial speed of 8.65
m/s from a
height of 29.6 m. After what time interval does it strike the
13. ground?
You know the initial velocity, the distance and the acceleration.
Which equation
in Table 2.2 will allow you to find the time? You may need to
use the quadratic
equation. s
12.–/1 pointsSerPSE8 2.P.042.My Notes |
The height of a helicopter above the ground is given by h =
2.80t3, where h is in
meters and t is in seconds. At t = 1.70 s, the helicopter releases
a small
mailbag. How long after its release does the mailbag reach the
ground?
s
13.2/4 points | Previous AnswersSerPSE8 2.P.043.MI.My Notes
|
A student throws a set of keys vertically upward to her sorority
sister, who is in a
window 2.00 m above. The second student catches the keys 2.30
14. s later.
(a) With what initial velocity were the keys thrown?
magnitude
Your response differs from the correct answer by more than
100%. m/s
direction
(b) What was the velocity of the keys just before they were
caught?
magnitude
The correct answer is not zero. m/s
direction
14.–/3 pointsSerPSE8 2.P.048.My Notes |
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Submissions Used
15. A student drives a moped along a straight road as described by
the velocity
versus time graph in the figure. The divisions along the
horizontal axis
represent 1.0s and the divisions along the vertical axis represent
2.0 m/s.
Sketch this graph in the middle of a sheet of graph paper. (Do
this on paper.
Your will need it to do part (a) and (b).)
(a) Directly above your graph, sketch a graph of the position
versus time,
aligning the time coordinates of the two graphs. (Do this on
paper. Your
instructor may ask you to turn in your work.)
(b) Sketch a graph of the acceleration versus time directly
below the velocity-
versus time graph, again aligning the time coordinates. On each
graph, show the
numerical values of x and ax for all points of inflection. (Do
16. this on paper. Your
instructor may ask you to turn in your work.)
(c) What is the acceleration at t = 6.0 s?
m/s2
(d) Find the position (relative to the starting point) at t = 6.0 s.
m
(e) What is the moped's final position at t = 9.0 s?
m
15.–/5 pointsSerPSE8 2.P.053.MI.My Notes |
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17. An inquisitive physics student and mountain climber climbs a
54.0-m-high cliff
that overhangs a calm pool of water. He throws two stones
vertically downward,
1.00 s apart, and observes that they cause a single splash. The
first stone has an
initial speed of 1.88 m/s.
(a) How long after release of the first stone do the two stones
hit the water?
s
(b) What initial velocity must the second stone have if the two
stones are to hit
the water simultaneously?
magnitude m/s
direction
(c) What is the speed of each stone at the instant the two stones
hit the water?
first stone m/s
second stone m/s