Physics quiz archive: energy conservation, momentum conservation

Physics 205A Quiz 4, fall semester 2017
Cuesta College, San Luis Obispo, CA
Sections 70854, 70855, version 1
Exam code: quiz04w33N



Sections 70854, 70855 results

0- 6 :
7-12 :	***** [low = 9]
13-18 :	****************
19-24 :	**************** [mean = 20.8 +/- 5.7]
25-30 :	*********** [high = 30]

Astronomy quiz archive: solar system

Astronomy 210 Quiz 4, fall semester 2017
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz04S4pR


Section 70158

0- 8.0 :
8.5-16.0 :
16.5-24.0 :	****** [low = 18.5]
24.5-32.0 :	******************* [mean = 30.7 +/- 5.8]
32.5-40.0 :	***************** [high = 40.0]

Section 70160, version 1
Exam code: quiz04N3rn


Section 70160

0- 8.0 :
8.5-16.0 :	* [low = 12.0]
16.5-24.0 :	***
24.5-32.0 :	************* [mean = 30.4 +/- 6.8]
32.5-40.0 :	************ [high = 40.0]

Physics midterm problem: world-record washing machine throw

Physics 205A Midterm 1, fall semester 2017
Cuesta College, San Luis Obispo, CA

"Washing Machine Throwing Showdown"
Guinness World Records
youtu.be/YC0oj7BcWiI

In 2017, Zydrunas Savickas set a world record throwing a 46 kg (101 lb) washing machine that landed a horizontal distance of 4.13 m from its starting position atop his head. Savickas' height is 1.91 m, and the washing machine was airborne for 1.84 s starting from just off the top of his head to just before hitting the ground[*].

Find both the horizontal and vertical components (v_0x, v_0y) of the initial velocity vector for the washing machine, as it was thrown and released from just above the top of Savickas' head. Neglect air resistance, and treat the washing machine as a point object. Show your work and explain your reasoning using properties of projectile motion.

[*] Rachel Swatman, "Watch Game of Thrones Star Take on World’s Strongest Man Winner in Washing Machine Throwing Showdown" (January 13, 2017), guinnessworldrecords.com/news/2017/1/watch-game-of-thrones-star-take-on-world%E2%80%99s-strongest-man-winner-in-washing-machi-458290.

Solution and grading rubric:

• p:
  Correct. Discusses/demonstrates:
  1. uses given values of t = 1.84 s and x = +4.13 m to solve for the initial (and constant) horizontal velocity v_0x (where t₀ = 0, x₀ = 0); and
  2. uses given values of t = 1.84 s and y = −1.91 m to solve for the initial vertical velocity v_0y (where t₀ = 0, y₀ = 0).
• r:
  Nearly correct, but includes minor math errors. May have intentionally or unintentionally used y = +1.91 m or y = 0 instead of y = −1.91 m.
• t:
  Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. At least has one initial velocity component correct, but other component has errors in addition to those listed in (r), such as setting v_y = 0 in y = (1/2)⋅(v_y0 + v_y)⋅t to solve for v_y0, or setting v_x = 0 in x = (1/2)⋅(v_0x + v_x)⋅t to solve for v_x0, etc.
• v:
  Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner.
• x:
  Implementation of ideas, but credit given for effort rather than merit.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Sections 70854, 70855
Exam code: midterm01mOoL
p: 20 students
r: 16 students
t: 12 students
v: 3 students
x: 1 student
y: 0 students
z: 0 students

A sample "p" response (from student 1956):

Astronomy midterm question: plausible waxing gibbous moon photomontage?

Astronomy 210 Midterm 1, fall semester 2017
Cuesta College, San Luis Obispo, CA

Shown at right[*] is a photographic montage of a moon, starlight sky, and a model. Discuss whether this composition is plausible or implausible for an observer in San Luis Obispo, CA, given the phase and position of the moon in the sky, and the presence of stars in the sky. (Ignore the effect of natural/artificial light sources that illuminate this picture.) Support your answer using a diagram showing the positions of the sun, moon, Earth, and an observer on Earth.

[*] @amandawalker247, instagram.com/p/BUdO48PluWk/.

Solution and grading rubric:

• p:
  Complete diagram and reasoning includes the following explanations:
  1. identifies the phase as a waxing gibbous moon;
  2. which is highest overhead at 9 PM, rises six hours earlier at 3 PM, and sets six hours after being highest overhead at 3 AM;
  3. the presence of stars indicates the sun is not up, so possible night times range from 6 PM to 6 AM;
  and thus concludes that the composition is plausible for 9 PM (or any time between 6 PM and 3 AM). May have included discussion on effect of moon's or San Luis Obispo's light pollution on stars, apparent lighter lower part of the sky coming from the sun, etc.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Diagram and/or explanation has minor errors.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to draw a moon phase diagram and apply rise/overhead/set times.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion not clearly based on a moon phase diagram.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 70158
Exam code: midterm01Sn0w
p: 21 students
r: 3 students
t: 4 students
v: 4 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 5966):

Astronomy midterm question: plausible waning gibbous moon photomontage?

Astronomy 210 Midterm 1, fall semester 2017
Cuesta College, San Luis Obispo, CA

Shown at right[*] is a photographic montage of a moon, starlight sky, and a model. Discuss whether this composition is plausible or implausible for an observer in San Luis Obispo, CA, given the phase and position of the moon in the sky, and the presence of stars in the sky. (Ignore the effect of natural/artificial light sources that illuminate this picture.) Support your answer using a diagram showing the positions of the sun, moon, Earth, and an observer on Earth.

[*] @amandawalker247, instagram.com/p/BUTABCll9rl/.

Solution and grading rubric:

• p:
  Complete diagram and reasoning includes the following explanations:
  1. identifies the phase as a waning gibbous moon;
  2. which is highest overhead at 3 AM, rises six hours earlier at 9 PM, and sets six hours after being highest overhead at 9 AM;
  3. the presence of stars indicates the sun is not up, so possible night times range from 6 PM to 6 AM;
  and thus concludes that the composition is plausible for 3 AM (or any time between 9 PM and 6 PM). May have included discussion on effect of moon's or San Luis Obispo's light pollution on stars, apparent lighter lower part of the sky coming from the sun, etc.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Diagram and/or explanation has minor errors.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to draw a moon phase diagram and apply rise/overhead/set times.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion not clearly based on a moon phase diagram.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 70160
Exam code: midterm01nDm3
p: 21 students
r: 3 students
t: 4 students
v: 4 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 3432):

Astronomy midterm question: Mars and Saturn rising after midnight?

Astronomy 210 Midterm 1, fall semester 2017
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board was asked and answered[*]:

Q: Well, I observed a bright red dot that is Mars rising just after midnight. At the same time there was another bright white dot right next to Mars. What is it?
A: I think it's Saturn.

Discuss how this answer is plausible for an observer in San Luis Obispo, CA, and how you know this. Support your answer using a diagram showing the positions of the sun, Mars, Saturn, Earth, and an observer on Earth.

[*] answers.yahoo.com/question/index?qid=20140311092430AAKTg2Q.

Solution and grading rubric:

• p:
  Complete diagram and reasoning includes the following explanations for an observer on Earth at or around midnight (12 AM):
  1. Mars can be placed in an orbit around the sun outside of Earth's orbit such that it is visible low over the observer's east horizon; and
  2. Saturn is also placed in an orbit around the sun outside of Earth's orbit such that it is visible low over the observer's east horizon.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Has east/west horizons switched, such that Mars and/or Saturn are setting at or around midnight.
• t:
  Problems with either diagram or discussion. Problems with either diagram or discussion. May have:
  1. observer placed at midnight, but has Mars and Saturn both high overhead; or
  2. observer not placed at midnight and east/west horizons switched.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Diagram and discussion problematic.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 70160
Exam code: midterm01Sn0w
p: 16 students
r: 9 students
t: 16 students
v: 4 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 1027):
Another sample "p" response (from student 2622):
A sample "r" response (from student 4472), with Mars and Saturn setting at midnight:

Astronomy midterm question: Mars and Venus low in the west at sunrise?

Astronomy 210 Midterm 1, fall semester 2017
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board was asked and answered[*]:

Q: Well, I observed a bright red dot that is Mars low in the west at sunrise. At the same time there was another bright white dot right next to Mars. What is it?
A: I think it's Venus.

Discuss how this answer is implausible for an observer in San Luis Obispo, CA, and how you know this. Support your answer using a diagram showing the positions of the sun, Mars, Venus, Earth, and an observer on Earth.

[*] answers.yahoo.com/question/index?qid=20140311092430AAKTg2Q.

Solution and grading rubric:

• p:
  Complete diagram and reasoning includes the following explanations for an observer on Earth at or around sunrise (6 AM):
  1. Mars can be placed in an orbit around the sun outside of Earth's orbit such that it is visible low over the observer's west horizon; and
  2. Venus, when placed anywhere in an orbit around the sun inside of Earth's orbit, can only be seen low over the east horizon at sunrise.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Has east/west horizons switched, such that Mars and/or Venus are setting at or around sunset.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Problems with either diagram or discussion. May have both Venus and Mars in an inner (or outer) orbit with east/west horizons switched, such that Venus and Mars are rising at or around sunrise (or sunset).
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Diagram and discussion problematic.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 70160
Exam code: midterm01nDm3
p: 14 students
r: 10 students
t: 9 students
v: 0 student
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 1352):
Another sample "p" response (from student 8954):

Astronomy quiz archive: telescopes

Astronomy 210 Quiz 3, fall semester 2017
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz03S3ir


Section 70158

0- 8.0 :	*** [low = 6.0]
8.5-16.0 :	*******
16.5-24.0 :	************* [mean = 23.1 +/- 7.8]
24.5-32.0 :	****************
32.5-40.0 :	***** [high = 40.0]

Section 71060
Exam code: quiz03Ni5t


Section 71060

0- 8.0 :	* [low = 7.5]
8.5-16.0 :	******
16.5-24.0 :	********** [mean = 24.0 +/- 7.5]
24.5-32.0 :	************
32.5-40.0 :	*** [high = 36.5]

Physics quiz archive: vectors, projectile motion, forces

Physics 205A Quiz 3, fall semester 2017
Cuesta College, San Luis Obispo, CA
Sections 70854, 70855 version 1
Exam code: quiz03T4uC



Sections 70854, 70855 results

0- 6 :
7-12 :	********* [low = 9]
13-18 :	****************
19-24 :	*********************** [mean = 19.2 +/- 5.2]
25-30 :	****** [high = 27]