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 110. The exam period was 90 minutes; the average score was 88.5; the median score was 92. 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 hydraulic lift with a rectangular platform of area A = 9 m^{2} is used to raise cars above the ground. The cross-sectional area of the narrow, fluid-filled tube connected to the lift-platform is 0.05 m^{2} (as shown in the figure).

If a 720-kg car is placed on the lift-platform what force F must be applied to the small piston to balance the weight of the car?

(a) 9.8 N (b) 14.3 N (c) 28.4 N (d) 39.2 N (e) 46.5 N

(a) d = 23 cm (b) d = 147 cm (c) d = 396 cm

Water (ρ_{w} = 1000 kg/m^{3}) flows though a cylindrical pipe of radius R_{1} = 8 cm with an unknown speed of v_{1}. The pipe then narrows to a radius R_{2} = 3.2 cm where the water has a speed of v_{2} = 8.13 m/s.

What is the speed of the water in the wide region of the pipe?

(a) v_{1} = 1.3 m/s (b) v_{1} = 3.3 m/s (c) v_{1} = 8.1 m/s (d) v_{1} = 20 m/s (e) v_{1} = 51 m/s

(a) 1.9 × 10^{3} s (b) 3.9 × 10^{3} s (c) 4.3 × 10^{3} s (d) 5.1 × 10^{3} s (e) 6.8 × 10^{3} s

(a) 4 kPa (b) 18 kPa (c) 32 kPa (d) 41 kPa (e) 55 kPa

A string is attached to a cube of wood of volume V = 0.3 m^{3} that is placed in fresh water with density 1000 kg/m^{3}, as shown in the figure below. The tension in the string, T, is 520 N.

What is the density of the wood?

(a) 212 kg/m^{3} (b) 496 kg/m^{3} (c) 614 kg/m^{3} (d) 823 kg/m^{3} (e) 1043 kg/m^{3}

(a) smaller than 520 N (b) equal to 520 N (c) larger than 520 N

An open U shaped tube is initially partially filled with water (ρ_{w} = 1000 kg/m^{3}). An 10 cm high column of oil (ρ_{oil} = 800 kg/m^{3}) is carefully poured into the right side of the tube (see picture). What is the height H of the oil above the water?

(a) H = 1 cm (b) H = 2 cm (c) H = 3 cm (d) H = 4 cm (e) H = 5 cm

A block suspended from a scale has a weight of 3 N. The block is then lowered into a glass of water so that it is completely submerged and the reading on the scale is 2.4 Newtons. (The density of water is 1000 kg/m^{3}).

What is the volume of the block?

(a) 8.94 × 10^{-6 }m^{3} (b) 3.01 × 10^{-5}m^{3} (c) 6.12 × 10^{-5} m^{3} (d) 1.04 × 10^{-5 }m^{3} (e) 4.06 × 10^{-4 }m^{3}

(a) remain at 2.4 N. (b) increase. (c) decrease.

(a) 100 m (b) 200 m (c) 300 m (d) 400 m (e) 500 m

(a) 128 kg (b) 332 kg (c) 480 kg (d) 594 kg (e) 932 kg

A 7.0 kg block is resting on a horizontal frictionless surface. A force F pushes the block to the right and a spring with spring constant 150 N/m pushes the block to the left, such that the block is in equilibrium. At time t = 0 the force F is removed and the mass oscillates back and forth with a maximum speed v = 2.1 m/s.

How long does it take the block to complete one oscillation?

(a) 0.43 s (b) 1.2 s (c) 1.4 s

(a) F = 68 N (b) F = 73 N (c) F = 91 N (d) F = 120 N (e) F = 150 N

(a) 1.21 m/s (b) 1.69 m/s (c) 1.79 m/s (d) 2.05 m/s (e) 2.41 m/s

(a) v(t) = V_{max} cos(ωt) (b) v(t) = -V_{max} cos(ωt) (c) v(t) = -V_{max} sin(ωt)

A simple 3 kg pendulum is suspended from the ceiling of an elevator. When the elevator is at rest, the period of the pendulum is 0.75 seconds.

What is the length of the pendulum string?

(a) 0.14 m (b) 0.24 m (c) 0.34 m

(a) moving up with a constant speed. (b) moving down with a constant speed. (c) accelerating up. (d) accelerating down. (e) at rest and it is not accelerating.

Standing 10 meters from a stopped ambulance, you notice the siren is 120 dB and the pitch is 500 Hz. Another day, while standing by the side of a road, you see the same ambulence driving and hear the siren but it is only 80 dB and the pitch is 540 Hz. (The speed of sound in air is 340 m/s.)

What is the speed of the ambulance?

(a) 27 m/s (b) 25 m/s (c) 23 m/s

(a) toward you (b) away from you.

(a) 100 m (b) 1000 m (c) 10000 m

A harpsichord string (fixed at both ends) is 0.8 meters long. The fundamental frequency is 500 Hz and the tension in the string is 158 newtons. (The speed of sound in air is 340 m/s.)

What is the speed of the transverse wave in the string?

(a) 600 m/s (b) 700 m/s (c) 800 m/s

(a) 2.5 × 10^{-4} kg/m (b) 3.5 × 10^{-4} kg/m (c) 4.5 × 10^{-4} kg/m

(a) 0.68 m (b) 0.80 m (c) 1.5 m

(a) 0.53 m (b) 0.78 m (c) 0.91 m