A new car manufacturer advertises that their car can go “from zero to sixty in 8 s.” This
is a description of
A) instantaneous speed.
B) average speed.
C) instantaneous acceleration.
D) average acceleration.
E) none of the given answers.
The moment of inertia of a uniform rod (about its center) is given by I = ML2/12. What
is the kinetic energy of a 120-cm rod with a mass of 450 g rotating about its center at
3.60 rad/s?
A) 0.350 J
B) 4.20 J
C) 0.700 J
D) 0.960 J
E) 2.10 J
The magnetic field due to a 2-A current flowing in a long, straight wire is 8 μT at a
point P, a certain distance away from the wire. How far is this point from the center of
the wire?
A) 2 cm
B) 3 cm
C) 4 cm
D) 5 cm
E) 6 cm
A mirror with a focal length -25 cm has a 4.0 cm tall object placed 100 cm in front of it.
What is the position of the image?
A) 20 cm behind the mirror
B) 25 cm behind the mirror
C) 100 cm in front of the mirror
D) 25 cm in front of the mirror
E) 20 cm in front of the mirror
An object is dropped from a helicopter. When it reaches terminal velocity
A) the acceleration finally reaches g.
B) gravity no longer acts upon it.
C) all of the upward forces add up to zero.
D) the total force is zero.
E) the acceleration of gravity, g, becomes 0.
At what speed must a 150-kg football player be moving to have the same momentum as
a 15.0-g bullet traveling at 300 m/s?
A) 10.0 m/s
B) 3.00 cm/s
C) 3.00 m/s
D) 30.0 m/s
E) 1.00 m/s
A polarizer (with its preferred direction rotated 30 to the vertical) is placed in a beam of
unpolarized light of intensity 1. After passing through the polarizer, the beam’s intensity
is
A) 0.2501.
B) 0.7501.
C) 0.5001.
D) 0.8661.
E) 0.5000.
Two equal forces are applied to a door at the doorknob. The first force is applied
perpendicular to the door; the second force is applied at 30 to the plane of the door.
Which force exerts the greater torque?
A) the first applied perpendicular to the door
B) the second applied at an angle
C) both exert equal non-zero torques
D) both exert zero torques
E) additional information is needed
A cable is 100-m long and has a cross-sectional area of 1 mm2. A 1000-N force is
applied to stretch the cable. The elastic modulus for the cable is 1.0 x 1011 N/m2. How
far does it stretch?
A) 0.001 m
B) 0.01 m
C) 0.10 m
D) 1.0 m
E) 10 m
In order for the atoms in a neon discharge tube (or a neon beer sign) to emit their
characteristic orange light, it is necessary that
A) there be no unoccupied energy levels in each atom.
B) each atom carry a net electric charge.
C) the atoms be continually replaced with fresh atoms, because the energy of the atoms
tends to be used up with continued excitation, resulting in dimmer and dimmer light.
D) electrons first be given energy to raise them from their ground state to an excited
state.
Jenny drives at a constant speed of 15 m/s around a circular drive of diameter 60
meters.
(a) Determine her acceleration in m/s2.
(b) Is her acceleration tangential, centripetal, or centrifugal?
(c) Is her velocity tangential, centripetal, or centrifugal?
Lenz’s Law is a consequence of the law of conservation of
A) mass.
B) momentum.
C) electric field.
D) energy.
E) charge.
A block lies on a smooth inclined plane tilted at an angle of 35 to the horizontal.
(a) Draw the free-body diagram for the block.
(b) Determine the block’s acceleration as it slides down the inclined plane.
(c) If the block started from rest 8.5 m up the incline from its base, determine the
block’s speed when it reaches the bottom of the incline.
(d) How long did it take the block to reach the bottom of the inclined plane?
Which one of the following would be expected to have the smallest BULK
MODULUS?
A) helium vapor
B) solid iron
C) liquid water
D) solid uranium
E) liquid mercury
A stationary proton is in a uniform magnetic field of 0.20 T. What is the magnitude of
the magnetic force on the proton?
A) zero
B) 1.6 x 10-20 N
C) 3.2 x 10-20 N
D) 1.6 x 10-21 N
E) 3.2 x 10-21 N
A nearsighted person has a near point of 12. cm and a far point of 17. cm. If the lens is
2.0 cm from the eye:
(a) what lens power will enable this person to see distant objects clearly?
(b) what then will be the new near point?
FIGURE 8-7
A uniform rod has a weight of 40. N and a length of 1.0 m. It is hinged to a wall (at the
left end), and held in a horizontal position by a vertical massless string (at the right
end), as shown in Fig. 8-7. What is the magnitude of the torque exerted by the string
about a horizontal axis which passes through the hinge and is perpendicular to the rod?
A) 40 m ∙ N
B) 10 m ∙ N
C) 5.0 m ∙ N
D) 20 m ∙ N
E) 30 m ∙ N
2.0 A in the 100-turn primary of a transformer causes 14 A to flow in the secondary.
How many turns are in the secondary?
A) 700
B) 356
C) 114
D) 14
E) 4
When a ball is thrown straight up, which of the following is zero at its highest point?
A) acceleration
B) displacement
C) velocity
The windings of a DC motor have a resistance of 6.0 Ω. The motor operates
on 120. V AC, and when running at full speed it generates a back emf of 105. V.
(a) What is the starting current of the motor?
(b) What current does the motor draw when operating at full speed?
The polarization of sunlight is greatest at
A) sunrise.
B) midday.
C) both sunrise and sunset.
D) sunset.
If the intensity of sound changes (increases) by a factor of 100, the decibel level
changes by a factor of
A) log 100.
B) 100.
C) 20.
D) 1.
E) 10.
A conductor is placed in an electric field under electrostatic conditions. Which of the
following statements is correct for this situation?
A) The electric field is zero inside the conductor.
B) All valence electrons go to the surface of the conductor.
C) The electric field on the surface of the conductor is perpendicular to the surface.
D) All of the other answers apply.
For this problem, assume that the acceleration of gravity is 10 m/s2 downward, and that
all friction effects can be neglected. A ball is thrown upward at a velocity of 20 m/s.
What is its velocity after 3 s?
A) zero
B) 10 m/s upward
C) 10 m/s downward
D) 20 m/s downward
E) 20 m/s upward
A girl throws a rock horizontally with a speed of 12.0 m/s from a bridge. It falls 2.28 s
before reaching the water below.
(a) How high is the bridge from the water below?
(b) How far horizontally does the rock travel before striking the water?
In order to produce beats, the two sound waves should have
A) slightly different amplitudes.
B) the same frequency.
C) the same amplitude.
D) slightly different frequencies.
A 100-W light bulb is connected to a 110-V source. What is the resistance of this bulb?
A) 100 Ω
B) 8.00 x 10-3 Ω
C) 6.00 x 10-3 Ω
D) 121 Ω
E) 242 Ω
Consider electrons flowing Southward along a horizontal power line. The magnetic
field generated directly below the wire by the current is pointing
A) Eastward.
B) Westward.
C) Northward.
D) Southward.
E) upward.
Electromagnetic radiation of wavelength 200. nanometers is which type?
A) X-rays
B) ultraviolet
C) microwaves
D) AM radio
E) visible
An ideal fluid in a pipe of diameter 14. cm is moving at 6.0 m/s.
(a) If the incompressible fluid density is 1.05 grams/cc, what is the flow rate in kg/s?
(b) What is the speed of flow if the pipe narrows to 4.0 cm radius?