G.C. Sloan: Physics 2305, Exam 2

Physics 2305: Exam 2 Results

Please keep in mind that the letter grades assigned to exams aren't used to determine final course grades; it's the numerical results that count.

Answer keys are below

Students: 243

Mean: 57.3

Std Dev: 18.1

A 24

B 57

C 97

D 34

F 31

Answers to multiple-choice questions

	Form A	Form B	Form C	Form D	Form E
1.	B	B	B	B	A
2.	A	A	C	C	C
3.	D	B	D	B	B
4.	B	C	C	C	B
5.	C	D	B	A	A
6.	B	B	C	A	C
7.	D	A	C	C	A
8.	A	A	B	B	D

Answers to free-form questions

The car wreck
a) v = (2 mu g d)^1/2 = 6.5 m/s for the larger car and 4.6 m/s for the smaller car (Forms A,C) or 6.2 m/s and 4.4 m/s respectively (Forms B,D);
b) v_i = v_S + v_L (m_L/m_S) = 13.2 m/s (A,C) or 12.7 m/s (B,D).

Tarzan
a) v = [(Tl/m) - gl]^1/2 = 4.3 m/s (Forms A,C) or 5.3 m/s (Forms B,D);
b) h = v²/2g = 0.93 m (A,C) or 1.5 m (B,D);
c) theta = cos^-1 (1 - h/l) = 25 degrees (A,C) or 31 degrees (B,D).

The ladder
theta = tan^-1 (1/2 mu) = 42 degrees (Forms A,C) or 50 degrees (Forms B,D).

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