StraighterLine PHY 250 General Physics All Graded Exams
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StraighterLine PHY 250 General Physics
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StraighterLine PHY 250 General Physics
StraighterLine PHY 250 General Physics All Graded Exams
PHY250_TW | Chapter 3: Dynamics
Started on Sunday, April 26, 2020, 7:31 PM
State Finished
Completed on Sunday, April 26, 2020, 8:27 PM
Time taken 55 mins 26 secs
Grade 132.00 out of 150.00 (88%)
Feedback You’re off ...
StraighterLine PHY 250 General Physics All Graded Exams
PHY250_TW | Chapter 3: Dynamics
Started on Sunday, April 26, 2020, 7:31 PM
State Finished
Completed on Sunday, April 26, 2020, 8:27 PM
Time taken 55 mins 26 secs
Grade 132.00 out of 150.00 (88%)
Feedback You’re off to a good start. A course grade of 70% is required to request a transcript. You’ve met that for the first exam already, but if you want to
reattempt for a higher grade you can retake this assessment (only the first graded assessment in this course can be retaken). Study hard for each
exam, and consider using tutoring anytime you get stuck. Remember that 10 hours of tutoring are provided to you through your StraighterLine
membership.
Question 1
What is the acceleration of a skydiver at terminal velocity whose mass is 80 kg and cross-sectional area is 14 m2. The density of the air he is falling
Correct through is 0.9984 g / m3. The drag coe_cient has a value of 0.485.
6.00 points out
of 6.00 Select one:
15.2 m / sec2
56.4 m / sec2
0 m / sec2
481 m / sec2
None of the above
The correct answer is: 0 m /sec2
Question 2 1
Calculate x = vt + 2at2 , where v = 0.227 m/s, t = 11.1s, and a = 9.80 m/s2 .
Incorrect
0.00 points out
of 6.00
Select one:
a. 606.2487 m
b. 606 m
c. 605.5 m
d. 606.249 m
The correct answer is: 606 m
Question 3
Which of the following statements concerning an object in free fall through the atmosphere is incorrect?
Correct
6.00 points out Select one:
of 6.00 Air resistance opposes the motion of an object moving through air and exists because a moving object collides with air molecules.
The speed of a falling object increases due to the frictional force of air drag.
Given two spherical objects made of the same material and dropped from the same height, the one with the larger cross-sectional area will
experience increased air resistance.
When the magnitude of the air drag equals that of the object's weight, the net force on the object is zero. The object then falls with a
maximum constant velocity called the terminal velocity.
The correct answer is: The speed of a falling object increases due to the frictional force of air drag.
,Question 4 A woman drives 2 blocks north, stops, continues on for another 4.5 blocks, and then makes a U-turn and drives south 3.25 blocks. After stopping
Correct momentarily she drives 5.75 blocks north. Which of the following is the magnitude of the woman’s displacement and distance traveled?
6.00 points out
of 6.00 Select one:
Displacement: 15.5 blocks
Distance: 15.5 blocks
Displacement: 15.5 blocks
Distance: 9 blocks
Displacement: 9 blocks
Distance: 15.5 blocks
Distance: 9 blocks
The correct answer is: Displacement: 9 blocks
Distance: 15.5 blocks
Question 5
Which of the following is a correct statement concerning the velocity of a particle in uniform circular motion?
Correct
6.00 points out Select one:
of 6.00 The velocity is in the same direction as the angular velocity.
The velocity is directed radially inward.
The velocity is in the same direction as the centripetal acceleration.
The velocity is constantly changing directions.
The correct answer is: The velocity is constantly changing directions.
Question 6
Incorrect
0.00 points out
of 6.00
Select one:
It isn’t.
All the cross-terms are equal to zero.
The vectors are 90° apart.
The vectors are pointing in the same direction.
The correct answer is: All the cross-terms are equal to zero.
Question 7
An airplane travels 600 m down a runway for take off. It starts from rest and moves with constant acceleration. It is in the air in 23 s. What is itsspeed
Correct when it takes off?
6.00 points out
of 6.00 Select one:
7.2 m / s
2.3 m / s
There is not enough information provided to answer the question.
The correct answer is: 52 m /s
,Question 8 Two children are playing catch in a passenger train. An observer on the ground measures that the train is traveling at 70 mph. As the train passes the
Correct observer, he measures that the ball is thrown with half of the speed as the passenger train. What velocity do the children measure for the ball?
6.00 points out
(Assume the positive direction is the direction in which the train is moving.)
of 6.00
Select one:
−105 mph
−70 mph
−35 mph
105 mph
The correct answer is: −35 mph
Question 9
What is the scalar product of two perpendicular vectors?
Correct
6.00 points out Select one:
of 6.00 the total of their magnitudes
the product of their magnitudes
zero
the difference of their magnitudes
The correct answer is: zero
Question 10 An airplane has an initial velocity with respect to the ground of 200 mph in an eastward direction. A strong wind begins to blow with a velocity of 80mph
Correct from north to south. What are the x-and y-components of the total velocity of the plane when the wind is taken into account? Let north be the positive y-
6.00 points out
direction and east be the positive x-direction.
of 6.00
Select one:
vx = +200 mph
vy = +80 mph
vx = +200 mph
vy = −80 mph
vx = +80 mph
vy = +200 mph
vx = +215 mph
vy = −80 mph
The correct answer is: vx = +200 mph
vy = −80 mph
Question 11
Consider a basket with 3.046 kg of fruit. When you weigh the whole package (fruit + basket), the reading on the scale is 4.2 kg. What is the most
Correct realistic weight of the basket alone?
6.00 points out
of 6.00 Select one:
a. 1.2 kg
b. 1.154 kg
c. 1.15 kg
d. 1 kg
The correct answer is: 1.2 kg
, Question 12 Which of the following is not an example of a vector?
Correct
6.00 points out Select one:
of 6.00 displacement
velocity
acceleration
mass
The correct answer is: mass
Question 13
Which is the definition of a derived unit?
Correct
6.00 points out Select one:
of 6.00 A unit which can be measured directly.
A unit which can not be measured directly.
A unit which is based on other (basic) units.
A unit which can be derived from a mathematical formula.
The correct answer is: A unit which is based on other (basic) units.
Question 14 A small mass is placed on a turntable that is rotating at 45 rpm. The centripetal acceleration is .
Correct
6.00 points out Select one:
of 6.00 greater when the mass is closer to the center of the circle
greater when the mass is farther from the center of the circle
independent of the location of the mass
zero
The correct answer is: greater when the mass is farther from the center of the circle
Question 15
Which of the following is not a frictional force between solids?
Correct
6.00 points out Select one:
of 6.00 static friction
kinetic friction
viscosity
rolling friction
The correct answer is: viscosity
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