True-false questions are worth 2 points each, three-choice multiple choice questions are worth 3 points each, five-choice multiple choice questions are worth 6 points each. The maximum possible score is 116. The exam period was 90 minutes; the average score was 83.9; the median score was 86. Click here to see page1 page2 of the formula sheet that came with the exam.

Unless told otherwise, you should assume that the acceleration of gravity near the surface of the earth is 9.8 m/s^{2} downward and ignore any effects due to air resistance.

A 3 kg mass attached to a spring sits at rest at its equilibrium position, as shown. At time t = 0 the mass is set in motion to the left with an initial velocity of 3.3 m/s. The angular frequency of this harmonic oscillator is ω = 4.2 rad/s.

How long does it take for the mass to complete one full cycle of its motion?

(a) 0.5 s (b) 1 s (c) 1.5 s

(a) v(t) = - 3.3 cos(4.2 t) (b) v(t) = 4.2 cos(3.3 t) (c) v(t) = 4.2 sin(3.3 t) (d) v(t) = - 3.3 sin(4.2 t) (e) v(t) = - 4.2 cos(3.3 t)

(a) 28 N/m (b) 53 N/m (c) 84 N/m

(a) 0.218 m (b) 0.366 m (c) 0.524 m (d) 0.786 m (e) 0.956 m

(a) 16.3 J (b) 25.8 J (c) 42.6 J (d) 55.9 J (e) 72.1 J

A string is stretched between a transducer and a support. It is held in tension by a mass hanging off one end. The length of the string L = 0.8 m and its mass density μ = 0.2 kg/m. The transducer excites a standing wave on the string as shown in the figure.

Is this wave transverse or longitudinal?

(a) transverse (b) longitudinal

(a) 9 kg (b) 18 kg (c) 24 kg (d) 36 kg (e) 44 kg

(a) 55 Hz (b) 63 Hz (c) 78 Hz (d) 92 Hz (e) 105 Hz

(a) 0.26 m (b) 0.44 m (c) 0.63 m (d) 0.87 m (e) 1 m

You are trying to study but your roommate is blasting his stereo so loud you cannot think. You are standing a distance 3 m away and measure the intensity of the sound to be I = 3.98 W/m^{2}.

What is the loudness of the sound?

(a) 105 dB (b) 112 dB (c) 119 dB (d) 126 dB (e) 131 dB

(a) 3.86 m (b) 4.02 m (c) 6.69 m (d) 12.8 m (e) 25.4 m

You are standing at a street corner listening to a fire engine, which is approaching you at a speed of 60 mph (26.8 m/s). The fire engine sounds its siren with a frequency f = 460 Hz. The speed of sound in air is 343 m/s.

At what frequency do you hear the siren?

(a) 436 Hz (b) 460 Hz (c) 499 Hz (d) 514 Hz (e) 554 Hz

(a) 405 Hz (b) 427 Hz (c) 448 Hz (d) 460 Hz (e) 477 Hz

(a) 100000 N/m^{2} (b) 106940 N/m^{2} (c) 114700 N/m^{2}

(a) -2.45 × 10^{6} N (b) -4.9 × 10^{5} N (c) 4.9 × 10^{5} N (d) 2.45 × 10^{6} N (e) 2.94 × 10^{6} N

(a) 200 kg/m^{3} (b) 300 kg/m^{3} (c) 400 kg/m^{3}

(a) 29 cm/s (b) 42 cm/s (c) 61 cm/s (d) 83 cm/s (e) 101 cm/s

A cylindrically shaped peg sits in a cup, as shown in the figure. You are asked to remove the peg without touching it. Remembering physics 101, you blow air across the top of the peg. The radius R of the peg is 0.02 m, and its mass is 0.01 kg. The density of air is 1.29 kg/m^{3}.

What is the minimum speed v_{air} required to lift the peg?

(a) 7 m/s (b) 9 m/s (c) 11 m/s

(a) It would be smaller. (b) It would be the same. (c) It would be bigger.

You are pushing water out of a syringe (the density of water is ρ = 1000 kg/m^{3}). The radius of the piston is 0.005 m, the radius of the needle is 0.001 m. The water exits the opening at 10 m/s. What force F are you applying to the piston of the syringe?

(a) F = 1.1 N (b) F = 1.4 N (c) F = 2.6 N (d) F = 3.3 N (e) F = 3.9 N

(a) faster (b) slower (c) unchanged

A ball of mass 12 kg is dropped onto a vertical, massless spring with spring constant k = 2000 N/m. The ball sticks to the spring and compresses the spring by as much as 0.2 m. What was the speed of the ball at the moment when it hit the top of the spring? Assume no energy was lost in the collision. (Hint: the gravitational potential energy of the ball changes as the spring is compressed).

(a) 0.757 m/s (b) 0.957 m/s (c) 1.257 m/s (d) 1.657 m/s (e) 1.957 m/s

(a) 1.75 Hz (b) 2.05 Hz (c) 2.40 Hz (d) 2.85 Hz (e) 3.15 Hz

(a) It would be bigger. (b) It would be the same. (c) It would be smaller.