Download Phys 141 Test 1 Fall 03

Solution to Midterm for phys141
Fall, 2004
Instructor: Li Ma
1. Which of the following is a fundamental quantity?
a. Weight
b. Velocity
c. Length
d. Minute
2. A car travels through a school zone at a speed of 5 m/s. What is the speed in mi/h? (1 m/s
= 2.24 mi/h)
a. 11.20 mi/h
b. 2.23 mi/h
c. 5.60 mi/h
d. 25.09 mi/h
3. The standard unit of length in the SI is which of the following?
a. Foot
b. Meter
c. Kilometer
d. Hand
4. Round off 0.0006757 to three significant figures and express it in standard powers-of-10
notation.
a. 67.57  10-5
b. 6.757  10-4
c. 6.75  10-4
d. 6.76  10-4
5. Compute the height in meters of Yao Ming who is 7 ft 6 in tall?
a. 2.545 m
b. 1.931 m
c. 2.286 m
d. 1.895 m
6. Which of the following is a scalar physical quantity?
a. Force
b. Velocity
c. Mass
d. Acceleration
7. If the speed of an object in uniform circular motion is doubled and the radial distance is
also doubled, then the centripetal acceleration increases by what factor?
a. 4
b. 3
c. 2
d. 1
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Solution to Midterm for phys141
Fall, 2004
Instructor: Li Ma
8. A rabbit starting to run from rest on a straight and level road is able to achieve a speed of
15 m/s in a time of 4.0 s. What is the rabbit’s average acceleration?
a. 60 m/s2
b. 3.75 m/s2
c. 9.8 m/s2
d. 120 m/s2
9. Which one of the following is correct about motion?
a. Motion is everywhere
b. Motion can be described in terms of speed and velocity
c. The object in motion is continuously changing its position
d. All of the above
10. The distance between Sun and Earth is about 1.5  108 km. The speed of light is 3.00 
108 m/s. How many seconds does it take the light to reach the Earth from Sun?
a. 4500 s
b. 500 s
c. 2 s
d. 0.5 s
11. Acceleration generally
a. is the time rate of change of velocity
b. is the time rate of change of speed
c. always has different direction from velocity
d. always has same direction as velocity
12. The average speed of the Earth revolving about the Sun is 3.0  104 m/s. Compute the
centripetal acceleration in m/s2 of the Earth in its nearly circular orbit about the Sun (r =
1.5  1011 m).
a. 5.0  10-3 m/s2
b. 5.0  10-3 m/s
c. 6.0  10-3 m/s2
d. 6.0  10-3 m/s
13. The motion of the horizontally projected object is combination of (air resistance is
neglected)
a. a freely falling motion and uniform motion in horizontal direction
b. a uniform circular motion and accelerating motion in horizontal direction
c. a uniform circular motion and uniform motion in horizontal direction
d. none of the preceding
14. Which of the following statement about force and motion is true?
a. A force can always produce a change in motion
b. In the absence of a net force, an object will be at rest
c. A net force is necessary for an object to be in motion with a constant velocity
d. A net force is necessary for an object to be accelerated
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Solution to Midterm for phys141
Fall, 2004
Instructor: Li Ma
15. A girl standing on a bridge drops a stone. If it takes 2.50 s for the stone to hit the water
below, what is the girl’s distance above the water?
a. 30.6 m
b. 24.5 m
c. 3.92 m
d. 25.5 m
16. An object is acted upon by a net force. Newton’s second law of motion tells us that
a. the net force is inversely proportional to the object’s mass in order to get the same
acceleration
b. with the fixed net force, the acceleration of the object is inversely
proportional to the object’s mass
c. to the same mass, the acceleration of the object is inversely proportional to the net
force
d. none of the preceding
17. Two 2.0-kg physical science textbooks on a bookshelf are 1.5 m apart. What is the
magnitude of the gravitational attraction between the books?
a. 3.6  10-8 N
b. 1.19  10-10 N
c. 6.67  10-15 N
d. 2.7  10-8 N
18. How would the force of gravity between two masses be affected if the separation distance
between them were increased by a factor of 3? Note: F1 is the force before changing, F2 is
the force after changing.
a. F2 = F1/3
b. F2 = F1/6
c. F2 = F1/9
d. F2 = 9F1
19. The constant G
a. is the same as g
b. is an universal constant
c. increases with increasing altitude
d. is proportional to the square of distance between two objects
20. In the metric system, the unit of the force is newton (N), what is the standard unit
equivalent to it?
a. m/(s2-kg)
b. kg-m-s2
c. kg-m/s2
d. kg-s2/m
21. The acceleration due to gravity
a. is an universal constant
b. is a fundamental property
c. is different for different objects in free fall
d. decreases with increasing altitude
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Solution to Midterm for phys141
22. Work
a.
b.
c.
d.
Fall, 2004
Instructor: Li Ma
is a scalar quantity
requires net force and motion
has a unit of joule in SI
all of the above
23. Linear momentum is conserved in the absence of
a. a change in velocity
b. an acceleration
c. a net force
d. a change in position
24. Angular momentum is conserved in the absence of
a. inertia
b. a net torque
c. gravity
d. linear momentum
25. Energy cannot be
a. destroyed
b. conserved
c. transferred
d. in more than one form
26. A 60-kg student traveling in a car with a constant velocity has a kinetic energy of 1.2 
104J. What is the speedometer reading of the car in km/h?
a. 20 km/h
b. 72 km/h
c. 1.2  104 km/h
d. 60 km/h
27. Which of the following objects has the greatest potential energy? An object with
a. a mass with 4m and height of h
b. a mass with 3m and height of 2h
c. a mass with 2m and height of 4h
d. a mass with m and height of 6h
28. A worker pushes horizontally on a large crate with a force of 480 N, and the crate is
moved 6.0 m. How much work was done?
a. 80.0 J
b. 3.0  103 J
c. 2.88  103 J
d. 2.88  104 J
29. Which of the following phrases best describes heat and temperature?
a. Heat is the same as temperature
b. Heat is energy in transit due to a temperature difference
c. Temperature is a measure of the internal energy of a substance
d. Temperature and heat are unrelated to energy
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Solution to Midterm for phys141
Fall, 2004
Instructor: Li Ma
30. From the equation H = mLf, we see that the units of latent heat of fusion are which of the
following?
a. J/kg-°C
b. kcal-kg/J
c. kcal/kg
d. kcal-kg/°C
31. Which temperature scale has the smallest degree interval?
a. Celsius
b. Fahrenheit
c. Kelvin
d. Absolute
32. Give the description of a solid, a liquid and a gas in terms of shape and volume
a. A solid and a liquid both have a definite shape and volume
b. A liquid has only a definite shape
c. A gas has a definite shape, but no definite volume
d. A gas has no definite shape or volume
33. The room temperature is 76 °F. What is it in Celsius degree?
a. 24.4°C
b. 169°C
c. 44°C
d. 349°C
34. Which of the following methods of heat transfer needs a material medium?
a. Only conduction
b. Only convection
c. Radiation
d. Both conduction and convection
35. About the amplitude and the energy of a wave, which of the following is NOT true?
a. The amplitude of a wave is the maximum displacement of any wave particle from
its equilibrium position
b. The amplitude of a wave will affect the wave speed
c. The energy transmitted by a wave is directly proportional to the square of its
amplitude
d. The energy transmitted by a wave is not related to its speed
36. A sound wave has a speed of 344 m/s and a wavelength of 0.665 m. What is the
frequency of this wave?
a. 1.99 × 10-3 Hz
b. 228.76 Hz
c. 517.29 s
d. 517.29 Hz
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Solution to Midterm for phys141
Fall, 2004
Instructor: Li Ma
37. What is true for longitudinal wave and transverse wave?
a. In a transverse wave, the oscillation of particles is parallel to the wave direction
b. In a longitudinal wave, the oscillation of particles is parallel to the wave
direction
c. In a longitudinal wave, the oscillation of particles is perpendicular to the wave
direction
d. None of the above
38. What is the period of the wave motion for ultrasound with a frequency of 50 kHz
a. 50 m
b. 50 s
c. 2.0 × 10-5 s
d. 2.0 × 104 s
39. What is the SI unit for frequency?
a. Meter
b. Second
c. Hertz
d. Length
40. Which of the following statement about radio waves is NOT true?
a. Radio waves are electromagnetic wave with relatively low speeds in vacuum
b. Radio waves are electromagnetic wave with relatively long wavelengths
c. Radio waves are electromagnetic wave with relatively low frequencies
d. Radio waves are not sound waves
41. Which of the following statement is true?
a. Electromagnetic waves are longitudinal waves
b. Electromagnetic waves require medium to propagate
c. All electromagnetic waves have same speed in vacuum
d. Radio waves are sound waves
42. What is NOT true about reflection?
a. The angle of reflection and the angle of incidence are equal to each other
b. The angle of reflection and the angle of incidence add to 90°
c. The angle of reflection and the angle of incidence are both measured relative to a
line of perpendicular to the reflecting surface
d. The reflected and incident rays are in the same plane
43. Light is incident on a plane mirror. The reflected rays have an angle of 40° relative to its
surface. What is the angle of incidence?
a. 40°
b. 50°
c. 45°
d. 90°
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Solution to Midterm for phys141
Fall, 2004
Instructor: Li Ma
44. Which of the following phenomena is NOT related to diffraction?
a. The waves are bent around the corners of the slit as they pass through
b. You talk in a room, a person standing outside around a corner can still hear you
c. You can see a colorful rainbow after rain
d. Radio waves can overcome the building so it makes the radio reception generally
quite efficient
45. What is speed of light in crown glass? (Hint: use the index of refraction)
a. 2.56 × 108 m/s
b. 1.97 × 108 m/s
c. 3.00 × 108 m/s
d. 5.07 × 10-9 m/s
46. When does total destructive interference occur?
a. When waves are in phase
b. When the waves have equal amplitudes and are completely out of phase
c. At the same time as total constructive interference
d. When total internal reflection occurs
47. The electric force between two charged bodies is
a. repulsive for both like and unlike charges
b. attractive for both like and unlike charges
c. an attract force and directly proportional to the production of the two charges
d. either attractive or repulsive, and inversely proportional to the square of the
distance between the two charges
48. The electric current is defined as
a. current / time
b. voltage / time
c. charge / time
d. resistance / time
49. The voltage is defined as
a. work / charge
b. charge / work
c. resistance / current
d. current / work
50. The Ohm’s law can be written as
a. charge = current × time
b. voltage = current × resistance
c. voltage = current × work
d. voltage = resistance × resistance
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Solution to Midterm for phys141
Fall, 2004
Instructor: Li Ma
51. A coffeemaker draws 10 A of current operating at 220 V. How much electrical energy
does the coffeemaker use each second?
a. 2200 J
b. 2200 Ω
c. 440 J/s
d. 22 W
52. The electric power is
a. P = IR
b. P = IV
c. P = BK
d. P = RC
53. What battery voltage is necessary to supply 0.70 A of current to a circuit with a resistance
of 20 Ω?
a. 9.8 V
b. 14 W
c. 14 V
d. 28 V
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