A sphere of pure U-235 will explode if it is
A) hot enough.
B) shaken hard enough.
C) big enough.
D) none of the above
If you hold two objects that have the same weight density, then they
A) may have unequal mass densities.
B) have equal mass densities.
C) are equal in weight.
Transformers use ac to satisfy the required
A) transfer of energy from coil to coil.
B) voltage for transformation.
C) change in magnetic field for operation.
D) change in input current.
E) magnetic field intensities.
The mass of air inside an average mid-size automobile is about
A) 0.2 kg.
B) 2 kg.
C) 20 kg.
D) 200 kg.
E) 2000 kg.
Credit for research in our knowledge of atomic spectra includes
A) Johann Jacob Balmer.
B) Johannes Rydberg.
C) Walter Ritz.
D) all of the above
E) none of the above
Figure E-2
A pendulum bob swings to and fro as shown in the sketch. The kinetic energy of the
bob
1) is maximum at position A,
2) is maximum at position B,
3) is the same at all positions,
and the potential energy is maximum at position
4) A.
5) B.
6) is the same at all positions.
The place from which motion is observed and measured is called
A) a frame of reference.
B) a starting point.
C) an initial location.
Water freezes at atmospheric pressure and a temperature of
A) 0 degrees Celsius.
B) 32 degrees Fahrenheit.
C) about 273 kelvin.
D) all of the above
E) none of the above
A roller skate at rest may have
A) speed.
B) velocity.
C) momentum.
D) energy.
A boy scout will be burned more severely by
A) 100 g of water at 100C.
B) 100 g of steam at 100C.
C) both about equally
D) neither of these
Suppose you put a chocolate layer on pieces of candy. Compared with the amount of
chocolate used to cover 1 pound of large pieces, if you cover 1 pound of smaller pieces
you’ll use
A) less chocolate.
B) the same amount of chocolate.
C) more chocolate.
D) makes no difference
For a system in mechanical equilibrium, the resultant
A) force must be zero.
B) torque must be zero.
C) both of these
D) none of these
On a cold day your feet feel warmer on a rug than on a tile floor because a rug
A) is usually warmer than tile.
B) is a poorer conductor.
C) for the same mass has more internal energy than tile.
D) all of the above
E) none of the above
A generator armature is more difficult to rotate when supplying electric current due to
A) an induced magnetic field in the windings that resists change.
B) increased resistance.
C) energy leaking as heat.
D) none of the above
A gymnast performing somersaults in a high-flying plane moving at constant velocity
needs to make
A) small adjustments to compensate for the airplane’s velocity.
B) major adjustments to compensate for the airplane’s velocity.
C) no adjustments.
D) none of the above
Release a ball inside a freely falling elevator and it falls directly in front of you instead
of “falling to the floor,” because you, ball, elevator, and enclosed air are in free fall. If
you do the same with a helium-filled balloon, the balloon will
A) also remain in front of you.
B) press against the ceiling.
C) press against the floor.
D) slowly rise.
E) slowly fall.
Wave interference occurs for
A) sound waves.
B) light waves.
C) water waves.
D) all of the above
E) none of the above
An electron and a proton are traveling at the same speed. Which has the longer
wavelength?
A) the electron
B) the proton
C) both the same
D) none of the above
The main reason a person weighs less at the equator than at the poles involves the
A) spin of the Earth.
B) influence of the Sun, Moon, and all the planets.
C) law of action and reaction.
The type of lens that spreads parallel light is a
A) converging lens.
B) diverging lens.
C) combination of converging-diverging lens.
A power line with a resistance of 2 ohms carries a current of 80 A. The power dissipated
in the line is
A) 40 W.
B) 160 W.
C) 320 W.
D) 12,800 W.
E) none of the above
If bits of the coals do not stick to your feet while walking barefoot on red-hot coals, it
would be best if your feet are
A) wet.
B) dry.
C) warm.
D) cold.
E) very hot.
A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball
initially at rest. The bowling ball and putty then move with a momentum of
A) 0 kg m/s.
B) 1 kg m/s.
C) 2 kg m/s.
D) 5 kg m/s.
E) more than 5 kg m/s.
The rotational inertia of a pencil is greatest about an axis
A) along its length, where the lead is.
B) about its midpoint, like a propeller.
C) about its end, like a pendulum.
Much of the charge on a conducting cube is
A) uniformly spread over its surface.
B) partly beneath the surface.
C) mutually repelled toward its corners.
D) none of the above
Electrons flow in an electrical circuit by
A) being bumped by other electrons.
B) colliding with molecules.
C) interacting with an established electric field.
D) none of the above
Superposition of waves can produce
A) reinforcement.
B) cancellation.
C) partial cancellation.
D) all the above
For radio reception in city buildings, diffraction is
A) helpful.
B) a hindrance.
C) not a factor.
Helium was first discovered in the
A) laboratory.
B) upper atmosphere.
C) Sun.
D) island of Helios, in Greece.
E) byproducts of nuclear fusion.
The superposition of identical waves affects
A) amplitude.
B) wavelength.
C) speed.
D) all of the above
E) none of the above
When an astronaut on the Moon experiences a solar eclipse, observers on Earth see
A) a lunar eclipse.
B) a solar eclipse.
C) no eclipse at all.
When you view color in a soap film with sunlight in back of you, a friend on the other
side of the soap film likely sees
A) the same color.
B) a different color.
C) only your head.