Question 1

An object is accelerating if it moves

Accepted Answer

A)  with constant velocity
B)  in a circular path
C)  in a straight-line pathBecause it is undergoing a change in its
D)  speed.
E)  direction.F) net force. B,E

Question 2

Which has a greater buoyant force?

Accepted Answer

A)  a huge lead zeppelin
B)  a small helium-filled balloon
C)  both
D)  neitherBecause
E)  of its low density.F) it occupies the greatest amount of space.G) it occupies the least amount of space.H) both have comparable densities. A,F

Question 3

Escape speed from Earth is about

Accepted Answer

A)  8 km/s.
B)  11.2 km/s.
C)  more than 11.2 km/s.Interestingly, if a stone released at rest at the far edge of the solar system drops to Earth by virtue of only Earth gravity, it will strike Earth's surface with a speed of about
D)  8 m/s
E)  10 km/sF) 11.2 km/sG) more than 11.2 km/s B,F

Question 4

Figure E/M-3
 
-Refer to the figure above. When the switch is closed in the primary circuit,

Accepted Answer

A)  voltage is established in the primary coil
B)  a current is established in the primary coil
C)  a magnetic field builds up around the primary coil
D)  all of the aboveAnd a voltage is induced in the secondary circuit principally because
E)  of the voltage in the primary.F) of the change of current in the primary.G) the expanding magnetic field about the primary is sensed by the secondary.

Question 5

A device that transforms electrical energy to mechanical energy is

Accepted Answer

A)  a generator,
B)  a motor,
C)  a transformer,
D)  any common magnet,And a device that transforms mechanical energy into electrical energy is a
E)  generator.F) motor.G) transformer.

Question 6

Figure M-6
 
-It would be easier to pull the hemispheres apart

Accepted Answer

A)  when they are at sea level
B)  if submerged several meters in water
C)  if high above the cloudsBecause
D)  external pressure on the hemispheres is lessened.
E)  water serves as a lubricant.F) the atmosphere exerts a pressure of 105 N/m2 on both hemispheres.

Question 7

Your lab instructor projects a ball horizontally from a lab bench that lands on the floor a horizontal distance away. Compared with the time the ball would take if simply dropped vertically from the bench, the time in the air for the projected ball is

Accepted Answer

A)  less.
B)  the same.
C)  greater.The horizontal distance from the bottom of the bench the ball travels in hitting the floor is equal the ball's initial speed
D)  multiplied by its time in the air.
E)  coupled with its speed of fall.F) squared plus its downward speed squared when hitting the floor.

Question 8

A pinhole cameras has no lens. The tiny pin-hole opening insures that rays of light from different parts of an object

Accepted Answer

A)  overlap.
B)  don't overlap.
C)  bend to a focus.Small openings between leaves in a tree act as pinholes. The round spots of light cast on the ground below are images of
D)  the Sun.
E)  the openings themselves.F) both of theseG) neither of these

Question 9

The Moon does not fall to Earth because

Accepted Answer

A)  the net force on it is zero.
B)  it is being pulled by the sun and planets as well as Earth.
C)  it is beyond the main pull of Earth's gravity.
D)  but it does fall!More specifically, the Moon
E)  is subject to both centripetal and centrifugal forces.F) interacts with all massive bodies, both near and far.G) is free of air resistance as well as other Earthly influences.H) continually falls around Earth rather than straight into it.

Question 10

An Earth satellite is in an elliptical orbit. The satellite travels faster when it is

Accepted Answer

A)  nearest Earth
B)  farthest from Earth
C)  constant speed everywhere in orbitAnd in close orbit travels faster when orbiting
D)  the Moon.
E)  Earth.F) both about the same for the same altitudes.

Question 11

A lunar month is about 28 days. If the Moon were closer to Earth than it now is, the lunar month would be

Accepted Answer

A)  less than 28 days,
B)  more than 28 days,
C)  still 28 days,Mainly because
D)  centripetal force would lessen with decreased distance.
E)  a closer Moon means an increase in both gravitational force and speed, which in a smaller orbit means shorter time.F) orbital speed about the center of mass of Earth-Moon system is not dependent upon the distance between Earth and Moon.G) of tidal friction.

Question 12

When the momentum of a punch is stopped by the fighter's jaw while he moves into the oncoming punch, the result is

Accepted Answer

A)  an increase in the relative velocity of the blow,
B)  a decrease in the time of contact of the blow,Which thereby most greatly increases the
C)  force.
D)  impulse.
E)  momentum.F) inertia.G) energy.

Question 13

A 100-newton sack of potatoes falls from an airplane. As velocity of fall increases, air resistance also increases, and when air resistance equals 100 N, the acceleration of the sack is

Accepted Answer

A)  zero
B)  5 m/s2
C)  10 m/s2
D)  100 m/s2And the velocity of the sack will be
E)  0 m/s.F) 5 m/s.G) 10 m/s.H) 100 m/s.I) constant.

Question 14

Neglecting all types of friction, if two identical sleds, one empty and the other with four heavy passengers, start sliding down a hill together, the heavier sled will get to the bottom

Accepted Answer

A)  before the empty car,
B)  after the empty car,
C)  at the same time as the empty car,While in the presence of air resistance, the heavier car will get to the bottom
D)  before the empty car.
E)  after the empty car.F) at the same time as the empty car.

Question 15

Jocko the clown at the top of a tall flagpole has considerable potential energy relative to the circus net below. After stepping off the pole and neglecting air resistance, his potential energy when he is half way to the net is

Accepted Answer

A)  the same as at the top,
B)  one quarter the amount at the top,
C)  one half the amount at the top,
D)  more than one-half the amount at the top,And compared to his kinetic energy when meeting the net, his kinetic energy at the half-way point is
E)  one half.F) the same as his potential energy at the half-way point.G) both of theseH) neither of these

Question 16

-Refer to the figure above. When the switch is closed in the primary circuit,

Accepted Answer

A)  voltage is established in the primary coil
B)  a current is established in the primary coil
C)  a magnetic field builds up around the primary coil
D)  all of the aboveAnd a voltage is induced in the secondary circuit principally because
E)  of the voltage in the primary.F) of the change of current in the primary.G) the expanding magnetic field about the primary is sensed by the secondary.

Question 17

Light from a laser is

Accepted Answer

A)  monochromatic.
B)  in phase.
C)  coherent.
D)  all of the above.Compared to the energy put into a laser, the energy of the laser beam is
E)  usually much more.F) much less.G) the same.

Question 18

The source of electrons lighting common lamps in your classroom is

Accepted Answer

A)  the power company,
B)  the electrical outlet,
C)  atoms in the lamp filament,
D)  the wires leading to the lamp,Whereas the source of energy that lights a common lamp in your home is
E)  the power company.F) the electrical outlet.G) atoms in the bulb filament.H) the wires leading to the lamp.

Question 19

In a series circuit of three identical lamps powered by a 1.5-volt dry cell, the voltage across each lamp is

Accepted Answer

A)  1/2 V.
B)  1 V.
C)  1-1/2 V.If any one of the lamps is disconnected, the other lamps will
D)  go out.
E)  continue to glow.

Question 20

Figure E/M-1
 
-Refer to the identical lamps above. If the current in lamp 1 is one ampere, then the current in lamp 2 is

Accepted Answer

A)  1/2 ampere,
B)  1/3 ampere,
C)  1 ampere,
D)  2 amperes,And the total current in the lamps and in the dry cell is
E)  0.F) 1/2 ampere.G) 1/3 ampere.H) 1 ampere.10) 3 amperes.

Exam 37: Systems of Measurement