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In the absence of air resistance, a ball of mass m is tossed upward to reach a height of 20 m. At the 10-m position, half way up, the net force on the ball is

mass*gravity m/g

When you drop a ball it accelerates downward at 9.8 m/s2. If you instead throw it downward, then its acceleration immediately after leaving your hand, assuming no air resistance, is

9.8 m/s

A heavy rock and a light rock in free fall (zero air resistance) have the same acceleration. The reason the heavy rock doesn't have a greater acceleration is that the

ratio of force to mass is the same.

A cannonball is fired horizontally at 10 m/s from a cliff. Its speed one second after being fired is about

14 m/s

Relative to the ground, an airplane gains speed when it encounters wind from behind, and loses speed when it encounters wind head on. When it encounters wind at a right angle to the direction it is

increases

A karate chop delivers a force of 3000 N to a board that breaks. The force that the board exerts on the hand during this event is

3000 N

A math book and a physics book are tied together with a length of string. With the string taut, one
book is pushed off the edge of a table. As it falls, the other book is dragged horizontally across the
table surface. With no friction, acceleration of the books is

a value between 0 and g

When an increase in speed doubles the momentum of a moving body, its kinetic energy

more than doubles

When an increase in speed doubles the kinetic energy of a moving body, its momentum

increases but less than doubles

Big brother and little sister can balance on a seesaw because of balanced

torques

When a spinning system contracts in the absence of an external torque, its rotational speed increases
and its angular momentum

remains unchanged.

Consider a ball rolling down an inclined plane. The normal force on the ball (the force perpendicular
to the plane).

is less than mass/gravity always

Consider a ball rolling in a horizontal circular path on the inside surface of a cone. The normal force on
the ball

is greater than mg always

When a ball at rest hangs by a single vertical string, tension in the string is mg. If the ball is made to
move in a horizontal circle so that the string describes a cone, string tension

is greater than mg always

Imagine you're standing on the surface of a shrinking planet. If it shrinks to one-tenth its original
diameter with no change in mass, on the shrunken surface you'd weigh

100 times as much

The fact that the Moon always shows its same face to Earth is evidence that the Moon rotates about its
axis about once per

month

The Moon is most responsible for Earth's tides. Which pulls more strongly on the Earth and its oceans?

sun

A spacecraft on its way from Earth to the Moon is pulled equally by Earth and Moon when it is

closer to the moons surface

Earth satellites such as the Space Shuttle orbit at altitudes that are above the Earth's

atmosphere

The mass of a classical atom comes mostly from its ____ ; and its volume from its ______.

nucleons; electrons

Consider a block of wood floating on water. If you push down on the top of the block until it's
completely submerged, the buoyant force on it

increases

An inflated balloon with a heavy rock tied to it submerges in water. As the balloon sinks deeper and
deeper, the buoyant force acting on it

decreases

The principal source of the Earth's internal energy is

radioactivity

The surface of Planet Earth loses energy to outer space due mostly to

radiation

The "greenhouse gases" that contribute to global warming absorb

more infrared radiation than visible.

In a mixture of hydrogen, oxygen, and nitrogen gases at a given temperature, the molecules having
the greatest average speed are those of

hydrogen

The electrical force of attraction between an electron and a proton is greater on the

Neither; both are the same.

Immediately after two separated charged particles are released from rest, both increase in speed. The
particles therefore have

either the same or opposite signs of charge.

Compared with the current in the white-hot filament of a common lamp, the current in the connecting
wire is

the same

As more lamps are connected in a series circuit, the current in the power source

decreases

As more lamps are connected in parallel in a circuit, the current in the power source

increases

A capacitor loses half its charge every second. If after five seconds its charge is q, what was its initial
charge?

32q

The magnetic force on a moving charged particle can change the particle's

direction

A step-up transformer in an electrical circuit can step up

voltage

The mutual induction of electric and magnetic fields can produce

light

All of the following are electromagnetic waves EXCEPT

None is outside the family; all are electromagnetic waves. radio waves, light waves microwaves, x rays

You swing to and fro on a playground swing. If you stand rather than sit, the time for a to-and-fro
swing is

shortened

ompared with the sound you hear from the siren of a stationary fire engine, the sound you hear
when it approaches you has an increased

frequency

During the time an aircraft produces a sonic boom, the aircraft is

flying faster than sound

The phenomenon of interference occurs for

both of these, light waves and sound waves

The speed of sound in air depends on

air temperature

Your friend states that under all conditions, any radio wave travels faster than any sound wave. You

agree with your friend

The phenomenon of beats results from sound

interference

To view your full-face image in a steamy mirror, compared to the height of your face, the minimum
height of the patch to wipe away is

one-half

Light reflecting from a smooth surface undergoes a change in

None of these
frequency
speed
wavelength

Which of these changes when light refracts in passing from one medium to another?

both of these
wavelength and speed

When white light passes through a prism, green light is bent more than

red light

When you look at the red petals of a rose, the color light you're seeing is

red

When the color yellow is seen on your TV screen, the phosphors being activated on the screen are

red and green

The red glow in the neon tube of an advertising sign is a result of

de-excitation

Polarization is a property of

transverse waves

Astrophysicists are able to identify the elements in the outer layers of a star by studying its

spectrum

If the Sun collapsed to become a black hole, Planet Earth would

continue on it's present orbit

Any atom that emits an alpha particle or beta particle

becomes an atom of a different element, always.

Suppose the number of neutrons in a reactor that is starting up doubles each minute, reaching one
billion neutrons in 10 minutes. When did the number of neutrons reach half a billion?

9 minutes

When a uranium nucleus undergoes fission, the energy released is primarily in the form of

kinetic energy of fission fragments.

When a fusion reaction converts a pair of hydrogen isotopes to an alpha particle and a neutron, most
of the energy released is in the form of

kinetic energy of the neutron.

Because there is an upper limit on the speed of particles, there is also an upper limit on

none of these

Relativistic equations for time dilation, length contraction, and relativistic momentum and energy
hold true at

all speeds

The equation E = mc
2
indicates that energy

and mass are closely related.

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