physics 117 mock midterm - answers · physics 117 mock midterm - answers . sunday, february 11,...

Physics 117 Mock Midterm - Answers Sunday, February 11, 2018 * 1 pm – Room 241 Arts Building *

Note: This mock test consists of questions covered in Physics 117. This test is not comprehensive. The problems on this test were compiled by your SSS peer mentors, and not your professors, and are based on problems from the textbook College Physics, Raymond Serway and Chris Vuille (9th, 10th, and 11th editions) and old exams from the website http://physics.usask.ca/~bzulkosk/phys117/index.html . **This mock test should not be viewed as a ‘preview’ of the actual test, and you should not rely solely on it for your test preparation.**

Format note: This mock exam consists of multiple choice questions and long-answer questions. The real multiple choice questions and ‘scratch-card’ questions rather than long-answer questions. Multiple Choice Answers

1 c 7 d 2 d 8 c 3 c 9 c 4 e 10 b and e 5 d 11 d 6 a 12 b and d

Detailed solutions to multiple-choice questions start on page 2. Answers to long-answer questions start on page 8.

Phys 117 Structured Study Session Information Mondays 4:30-5:50pm - Room 102 in the Murray Library (Yen) Tuesdays 2:30-3:50pm – Room 104 in the Arts Building (Michael) Wednesdays 3:30-4:50pm – Room G3 in the Murray Library (Jason)

http://physics.usask.ca/%7Ebzulkosk/phys117/index.html

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Answers will be posted on the Structured Study Session web page: http://library.usask.ca/sss

Part A – Multiple Choice Questions 1. Answer: (c)

By Pascal’s Principle, a change in pressure applied to a confined fluid is transmitted to every point of the fluid and its container, thus 𝑃𝑃 is constant. Because 𝑃𝑃 = 𝐹𝐹

𝐴𝐴 and 𝑃𝑃 is constant, we

know 𝐹𝐹1𝐴𝐴1

= 𝐹𝐹2𝐴𝐴2

. Answer is continued below.

2. Answer: (d) We must assume that Q is constant in the pipe filled with fluid and 𝑄𝑄 = 𝐴𝐴𝐴𝐴. So 𝐴𝐴1𝐴𝐴1 = 𝐴𝐴2𝐴𝐴2. Answer is continued below.

3. Answer: (c)

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4. Answer: (e)

5. Answer: (d) Doubling the amplitude would change energy (since 𝐸𝐸 = 1

2𝑘𝑘𝐴𝐴2), maximum speed (since 𝐴𝐴𝑚𝑚𝑚𝑚𝑚𝑚2 =

𝑘𝑘𝑚𝑚𝐴𝐴2), and maximum acceleration (since 𝐹𝐹 = 𝑚𝑚𝑚𝑚 = −𝑘𝑘𝑥𝑥2, maximum acceleration would depend

on 𝑥𝑥, and therefore on amplitude). Since the formula for period is 𝑇𝑇 = �𝑚𝑚𝑘𝑘

(2𝜋𝜋), and amplitude

does not occur in the formula, the period does not change after doubling the amplitude. (d)

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6. Answer: (a)

For mass 𝑚𝑚, let the period be 𝑇𝑇0. Recall: 𝑇𝑇0 = �𝑚𝑚𝑘𝑘

(2𝜋𝜋).

For mass 4𝑚𝑚, the period would be 𝑇𝑇4 = �4𝑚𝑚𝑘𝑘

(2𝜋𝜋).

So 𝑇𝑇4𝑇𝑇0

=�4𝑚𝑚𝑘𝑘 (2𝜋𝜋)

�𝑚𝑚𝑘𝑘 (2𝜋𝜋)=

�4𝑚𝑚𝑘𝑘

�𝑚𝑚𝑘𝑘

= ��4𝑚𝑚𝑘𝑘 �

�𝑚𝑚𝑘𝑘�= �4𝑚𝑚

𝑘𝑘𝑘𝑘𝑚𝑚

= √4 = 2. In other words, 𝑇𝑇4 = 2𝑇𝑇0.

(Alternative method: 𝑇𝑇4 = �4𝑚𝑚𝑘𝑘

(2𝜋𝜋) = √4�𝑚𝑚𝑘𝑘

(2𝜋𝜋) = 2�𝑚𝑚𝑘𝑘

(2𝜋𝜋) = 2𝑇𝑇0 .)

7. Answer: (d)

8. Answer: (c)

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9. Answer: (c)

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10. Answers: (b) and (e)

11. Answer: (d)

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12. Answers: (b) and (d)

End of Part A

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Part B – Long Answer Questions B1. Answers (a)

(b)

(c)

(d)

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Question B1, continued (e)

(f)

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B2. Answers

(a)

(b)

𝑚𝑚 = 0.250 kg

𝐴𝐴 = 0.125 m

|𝐴𝐴0| = 3.00 m/s

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Question B2, continued (c)

B3. Answers (a)

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Question B3, continued (b)

B4. Answers

(a) The yellow submarine is the source of the sound. (b) The red submarine carries the observer. (c) The motion of the observer will increase the time between pressure maxima. Then the

observed period will be longer, which will make the observed frequency lower since 𝑓𝑓 = 1𝑇𝑇.

(d) The sign of 𝐴𝐴0 should be negative since the red submarine is moving away from the yellow submarine.

(e) The motion of the source will decrease the time between pressure maxima. This will decrease the period, which will increase the observed frequency.

(f) Since the source is moving towards the observer, the sign of 𝐴𝐴𝑠𝑠 should be positive.

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Question B4, continued (g)

End of Part B

Student Learning Services (SLS) is a unit of the University Library that offers learning support to students. You can find information about the following services for students on the SLS website (http://library.usask.ca/studentlearning):

• Study Skills • Writing Help • Math & Stats Help • Structured Study Sessions for Phys 117, Bio 120, and Chem 112 • Workshops on topics such as research skills, exam preparation, etc.

Visit the University Library website (http://library.usask.ca) for information on other Library services and programs.

http://library.usask.ca/studentlearning

http://library.usask.ca/

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Want to help other students? Apply to be a PAL Peer Mentor for Fall 2018!

We are recruiting volunteers for the Peer Assisted Learning (PAL) program for the 2018/2019 academic year. Develop your leadership, mentorship and presentation skills while assisting other students to be successful. We are seeking students who are:

• interested in sharing their own academic experiences in an interactive and informal setting;

• upper year students with a 75% average or higher; and • who are available 5-10 hours/week depending on the volunteer role

Deadline to apply is Friday March 9th, 2018.

Need more information?

Attend a 30-minute information session, led by a current peer mentor, or visit our website library.usask.ca/pal to learn more or apply. Questions? [email protected]

Information Sessions (30-minutes, in Murray Library)

Tuesday February 13th, 11:30 am and 12:00 pm in room 102 Wednesday February 14th, 1:30 pm and 2:00 pm in room 102 Wednesday February 28th, 2:30 pm and 3:00 pm in room 102 Thursday March 1st, 11:30 am and 12:00 pm in room G3 Tuesday March 6th, 4:00 pm and 4:30 pm in room 102 Wednesday March 7th, 3:30 pm and 4:00 pm in room 102.

physics 117 mock midterm - answers · physics 117 mock midterm - answers . sunday, february 11,...

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