[기출문제] 홍익대 일반물리학(대학물리학) 2022-1 기말 기출문제 (정답 포함)

*Use the acceleration of gravity g = 10.0 \text{m/s}^2. Questions in boxes are concept problems.

1. Estimate the force exerted on your eardrum due to the water when you are swimming at the bottom of a pond that is 5.00 \text{m} deep. Use g = 10.0 \text{m/s}^2.
   (a) 5.00 \text{N}
   (b) 10.0 \text{N}
   (c) 15.0 \text{N}
   (d) 30.0 \text{N}

2. A gardener uses a water hose to fill a 30.0 \text{L} bucket. The gardener notes that it takes 2.00 \text{min} to fill the bucket. A nozzle with an opening of cross-sectional area 0.500 \text{cm}^2 is then attached to the hose. The nozzle is held so that water is projected horizontally from a point 1.00 \text{m} above the ground. Calculate the speed of the horizontally projected water. Use 1 \text{L} = 10^3 \text{cm}^3.
   (a) 10 \text{m/s}
   (b) 5 \text{m/s}
   (c) 30 \text{m/s}
   (d) 30 \text{cm/s}

3. Four springs to which small particles are tied at their ends are compressed from their equilibrium position at x=0, and released for their oscillation. Find the systems with the same maximum speeds.
   (a) a, d
   (b) a, c
   (c) b, d
   (d) c, d

4. An object of mass M oscillates harmonically on the end of a spring without energy loss. To double the period, which mass must the replaced object have?
   (a) 4M
   (b) 2M
   (c) M/4
   (d) M/2

5. Find the equation y(x, t) of a transverse sinusoidal wave located initially at x=0, t=2\text{s} that travels to the -x direction. The amplitude is 2 \text{m}, wavelength 4\text{m} and frequency 10\text{Hz}. Use SI units.
   (a) 2 \cos [2 \pi(x + 10t)]
   (b) 2 \cos [2 \pi(x + 10t) + \pi/2]
   (c) 2 \sin [2 \pi(x - 10t)]
   (d) 2 \sin [2 \pi(-x + 10t) + \pi/2]

6. You are driving at 75 \text{km/h}. Your sister follows in the car behind at 75 \text{km/h}. When you honk your horn, your sister hears a frequency that is _____________________.
   (a) higher than the frequency your hear.
   (b) lower than the frequency your hear.
   (c) the same as the frequency your hear.
   (d) You cannot tell without knowing the horn's frequency.

7. What is the length of the shortest pipe closed on one end and open at the other end that will have a fundamental frequency of 0.060 \text{kHz} on a day when the speed of sound is 340 \text{m/s}?
   (a) 4.12 \text{m}
   (b) 2.14 \text{m}
   (c) 1.42 \text{m}
   (d) 1.24 \text{m}

8. For objects at thermal equilibrium, which of the following is true?
   (a) Each is at the same temperature
   (b) Each has the same internal energy
   (c) Each has the same heat
   (d) All of the above

9. A tire is filled with air at 27^{\circ}\text{C} to a gauge pressure of 230 \text{kPa}. If the tire reaches a temperature of 37^{\circ}\text{C}, what fraction of the original air must be removed if the original pressure of 230 \text{kPa} is to be maintained? (unit: \%)
   (a) \frac{28}{300}
   (b) \frac{13}{300}
   (c) \frac{100}{52}
   (d) \frac{100}{58}

10. A pan of room-temperature water is sitting on a hot stove. Assume that volume of water in the pan doesn't change and temperature increases. Choose the correct signs for the work W done on the water in the pan and internal energy change \Delta E_{\text{int}}.
   (a) 0, +
   (b) +, +
   (c) 0, -
   (d) -, -

a, b, a, a, a, c, c, a, b, a