PY 131 Conceptual Academy Chapter 10 Quizzes

An object moving sideways through the air is

pulled downard by gravity.

How many meters does the surface of Earth curve downward across an 8 km tangential distance?

5 meters.

**Orbiting space satellites are above Earths**

atmosphere

PE + KE will be constant for a satellite in

both circular and elliptical orbits.

No component of gravitational force in the direction of travel occurs for a satellite in

circular orbit

A satellite travels slowest when it is

farthest from Earth.

According to Kepler, planets move around the Sun

in an elipse

At apogee, a satellite has the highest

potential energy and slowest speed.

An elliptical orbit around Earth is only possible at speeds

slower than 11.2 km per second.

The horizontal and vertical components of velocity for a projectile are

independent of each other.

A projectile is launched at 30 degrees above ground level. What other angle at the same speed will result in the same range?

60 degrees

(30 + 60 =90)

How far below a straight-line path does a horizontally-projected projectile fall in the first second of fall?

5 meters.

About how far below a straight-line path does a satellite in close Earth orbit fall in the first second of fall?

5 meters.

For an Earth satellite in circular orbit, list all the values that do not change.

Only speed, gravitational force, and distance from Earth. (not the Sun)

For an Earth satellite in an elliptical orbit, list all the values that do change.

Speed, gravitational force, and distance from the Sun and Earth.

The foci of the elliptical path for an Earth satellite are

one at Earth's center and the other elsewhere.

Kepler was the first to be credited for discovering that planets follow

elliptical paths

The kinetic energy of a satellite remains constant when the satellite follows a

circular path

Escape speed from Earth is any speed equal to or greater than

11\.2 km/s

A satellite traveling in a circle has constant

All of these (speed, acceleration, radial distance)

The reason that the Moon does not collide into Earth is

the Moon has a sufficient tangential speed.

At what location is the angular momentum of a satellite greatest?

The same at apogee and perigee.

At what location on Earth is a rocket easiest to launch into space?

South Point, Hawaii.

Relative to the water, a beaver swims eastward at 1 m/s across a 100 meter river flowing southward at 1 m/s. To move straight across the river without moving downstream, how should the beaver be pointed?

nowhere

A baseball player at the edge of a cliff throws a ball horizontally 5 meters above the ground. If the ball lands 20 meters away, the player has a throwing speed of

about 20 m/s

A rifle expert fires a bullet aimed 3 degrees below the horizontal. At the same moment, another bullet is simply dropped. The bullet first to hit the ground is

the fired one

Low-Earth orbit is about 8 kilometers per second. Low-Jupiter orbit around planet Jupiter is

more

A model airplane flies 14.1 kilometers per hour to the northwest. Its velocity as directed northward is

10 km/h

Flying at 40 meters per second at an altitude of 50 meters above the ground, a pilot drops a heavy crate that then hits the ground

beneath the plane

A projectile shot straight upward from Earth's surface at 8 kilometers per second will

rise and fall back to the earth's surface

A ball is projected upward at a 60 degree angle above the horizon. Neglecting air resistance, what happens to the vertical velocity when rising?

It decreases.

A pellet is shot vertically at 40 meters per second. Without wind resistance, it will return with a speed of

40 m/s

Low-Earth orbit for satellites is about 8 kilometers per second. Low-Moon orbit around the Moon is

less than 8 km/s

Planets do not crash into the Sun due to

their tangential velocities

Relative to the water, a beaver swims eastward at 1 m/s across a 100 meter river flowing southward at 1 m/s. How long does it take for the beaver to cross the river?

100 s.

A bullet is fired upward at a forty-five degrees from the horizon in the direction of a straight line. With respect to the straight line where is the bullet after one second?

about 5 m below the straight line

In what direction did Kepler propose for forces acting on planets?

along their directions of travel

According to Kepler, in what geometrical shape do planets orbit Sun?

ellipses

A stone gently released from the edge of our solar system falls down to Earth and reaches a speed of about

11\.2 km/s

A rock is tossed straight out horizontally from the roof of a tall building. After 1 second, how far downward has it traveled?

5 m

Weather satellites remain at a fixed position in the sky because they are

orbiting the earth with a 24 hour period

Why are satellites launched to altitudes typically higher than 200 kilometers?

above the atmosphere

How does the orbital velocity around the Moon and Earth compare when at an altitude of 400 kilometers?

The orbital velocity around the Moon is slower.

If moving farther away from Earth, the orbital speed of the Moon would

slow down

Low-Earth orbit takes about 90 minutes. If a satellite orbited as far away as the Moon, a single orbit would take about

about 28 days

A 60-kg woman weighing 600 newtons on Earth finds herself free floating in an orbiting space station where she has

less weight and same mass

A bowling ball rolls off the edge of a flat table. After leaving the table its horizontal component of speed

remains constant

What do we mean in saying a satellite has a "tangential velocity" in orbit around Earth?

its velocity parallel to the surface of the earth

A planet that traces an elliptical orbit moves at a constant

none of these (not speed, velocity, or acceleration)

A ball is projected upward at a 60 degree angle above the horizon. Neglecting wind resistance, what happens to the horizontal velocity as it rises?

it remains unchanged

The period of an orbiting satellite depends upon its

radial distance

With no air resistance a bullet shot 100 meters per second from a horizontally-held rifle will in one second travel

100 m

It presently takes about 28 days for the Moon to revolve once around Earth. If the Moon were closer, the time would be

less than 28 days

An orbiting space station doesn't crash into Earth because of

nothing; they are continually falling as they orbit the earth

With respect to the water, a boat travels eastward at 1 m/s across a 100-meter river flowing southward at 1 m/s. Relative to its starting position, where is the boat when reaching the east bank?

100 m farther south than where it started

A ball launched at 60 degrees hits a down-range target. The ball would reach the same range if launched at

30 d

Relative to the water, a beaver swims eastward at 1 m/s across a 100 meter river flowing southward at 1 m/s. When the beaver reaches the east bank, how far has it traveled relative to Earth?

141 m

A rocket that blasts off straight up from Earth and maintains a speed of 8 kilometers per second will

escape from the earth

A satellite moves faster in an elliptical orbit when

nearest to the earth

At what time does the force due to gravity do work to a satellite?

When the satellite is in a elliptical orbit

A model airplane flying at 10 kilometers per hour in a 10 kilometer per hour crosswind has a ground speed of

14\.1 km/h

A rifle expert fires a bullet from his rifle aimed 5 degrees above the horizontal. At the same instant, another bullet is simply dropped. The bullet first to hit the ground is

\n **the dropped one (I feel like this answer is wrong but CA says it is???)**

A rock tossed at 15 degrees above the horizon travels as far down range as if it were tossed at

75 d

A model plane with an airspeed of 20 km/h in a 20 km/h crosswind has a ground speed of about

28 km/h

Neglecting air resistance, a projectile shot straight upward from Earth's surface at 9.82 kilometers per second will

rise and fall back to the earth's surface to about the same location

The distance traveled by a planet in an elliptical orbit is greater when the planet is

closest to the star

An Earth satellite orbiting around Earth is

freely falling around the earth

Which hits its target in the shortest time: A ball projected upward 30 degrees or a same-speed one projected at 60 degrees?

the ball shot 30 degrees

On a clear early night, two satellites can be seen close together in the sky. The one appearing to be moving faster is

in lower orbit

Under what condition is angular momentum conserved for a satellite in orbit?

both of these (both circular and elliptical orbits)

Earth has an orbital speed of about 30 kilometers per second about the Sun. If slower, it would crash into the Sun. If faster, it would escape the solar system. Which scenario would require more energy?

Causing Earth to escape the solar system.

From a 20 meter tall tower, a bullet is fired horizontally at 300 meters per second over perfectly flat gound. Assuming no air resistance, the bullet will travel downrange a distance of

600 m

Any upwardly-thrown object once airborne has an acceleration of

1 g downward

Immediately after a ball thrown straight upward reaches its maximum height, its acceleration is

the same as it was at the top of its path

At what location is the acceleration of a satellite greatest?

at perigee

What planet in any solar system moves with greater speed?

the planet nearest the star

In order that a satellite escape our solar system it

must somehow gain speed greater than 11.2 km/s

The orbital speed of a planet around any star depends upon its

distance from the star

The Moon's orbit around Earth has greatest speed when it is

closest to the earth

An astronaut with apparent weightlessness in an orbiting space station is

like the station pulled by earth's gravity

Geosynchronous satellites remain above a fixed position on Earth's equator because

its orbital period is 24 hours

Saturn takes much longer than Earth in orbiting the Sun because it

has farther to go and because it orbits slower

On the Moon with a negligible atmosphere, a horizontally-fired bullet maintains a constant horizontal speed because

it is not acted on by any horizontal forces

What is the shape of orbit for a satellite with a radial velocity of zero?

circular

The farther a satellite orbits about Earth, its period becomes

longer

A basketball is thrown straight upward. Strictly speaking and considering air resistance, how long does it take for the ball to come down?

It takes longer to come down than go up

A satellite in an elliptical orbit travels at an increased speed when directly over a

none of these

Which of these is not a vector quantity?

speed

To launch a rocket in an elliptical orbit to escape velocity, is it more efficient to fire the rockets during apogee or perigee? (Consider: Force x distance = change in kinetic energy)

perigee, where it is closest an fastest

At what point does a bullet shot from a horizontally-held rifle start to fall?

as soon as it leaves the barrel

Earth orbits at 30 kilometers per second about the Sun. If slower, it would crash into the Sun. If faster, it would escape the solar system. A greater change would be required to

crash earth into the sun

Fired horizontally from Newton's hypothetical tall mountain at a speed of 8 kilometers per second, a projectile would

(all of these) trace a curve that matches the earth's curve, accelerate downward at g and return later to its starting position and repeat its falling behavior

What do we mean in saying a satellite has a "radial velocity" in orbiting Earth?

its velocity perpendicular to the surface of the earth