APHY101 EXAM QUESTIONS WITH
100% CORRECT ANSWERS
Which special place in the Earth's orbit is the Sun located at? - ANSWER- Occupied
Focus
In an elliptical orbit around the Earth, you will have the maximum energy of position
when you're at - ANSWER- Apogee or Apoapsis
Earth's seasons are caused by - ANSWER- the tilt of the Earths rotation axis
During most of the MESSENGER probe's journey from Earth to Mercury, it was -
ANSWER- speeding up with respect to the sun
You are orbiting the Sun and fire your engines at perihelion to SPEED UP. As a result: -
ANSWER- aphelion increases, perihelion stays the same
During a launch, the energy in your fuel is being converted into - ANSWER- heat,
energy of position, energy of motion
For the first few seconds after liftoff, which forces are important? - ANSWER- Gravity
and thrust
You're orbiting the Earth every 2 hours, and then you make a maneuver that increases
your orbital speed. Your NEW orbit will have a period that is - ANSWER- more than 2
hours
You're orbiting the Earth at 7.8 km/sec in a circular orbit. If you slow down to 7.7
km/sec, your new orbit will be circular but will be a bit closer to the Earth. (T/F) -
ANSWER- F - In many situations, if you slow down, you will fall into a lower orbit (but
note, if you started in a circular orbit, the new orbit will be elliptical - that's the first
reason the answer is FALSE here). Also, in this case, you need to remember that 7.8
km/sec is the MINIMUM speed required to be in the lowest possible Earth orbit. If you
slow down a little bit, your new orbit will become an ellipse with the perigee INSIDE THE
EARTH! In other words, your flight will become suborbital and you will fall to the ground.
You're in an elliptical orbit around the Earth. At perigee you increase your speed from
11 km/sec to 12 km/sec. The new orbit will be an elliptical orbit with a higher apogee.
(T/F) - ANSWER- F - In some cases, speeding up will get you to a larger elliptical orbit
with a higher perigee. But remember that 11.2 km/sec is the Earth's ESCAPE SPEED -
beyond this, the orbit changes shape and becomes hyperbolic. No apogee!
Your spacecraft is heading east in an orbit around the Earth. You want to get to a higher
orbit. To make this maneuver you must first make sure that your nozzle is facing -
, ANSWER- West - Another question that tests you on multiple concepts. To get to a
higher (larger) orbit you know you must SPEED UP. This means the nozzle must point
toward where you came from (in this case, the west) in order to achieve a speedup
when you fire the engines. Had the nozzle been pointing east, if you fired the engines
you'd SLOW DOWN and drop to a lower orbit.
When do experience maximum acceleration during a launch? - ANSWER- Just before
burnout
The period of the Earth-Mars Hohmann transfer orbit is 16 months. It is therefore
possible to get to Mars by a Hohmann transfer orbit in - ANSWER- 8 months
When you are many millions of kilometers away from any planet, moon, asteroid, or
comet, then you are not in orbit around anything at all. (T/F) - ANSWER- F - As long as
you're within the Solar System, in this case you'll be orbiting the Sun. Even though the
Sun may also be very far away from your location, it's so massive that its gravitational
pull dominates.
For most of the journey from Earth to Jupiter, you'll measure your velocity with respect
to - ANSWER- the center of the Sun
Russia fuels its rockets with kerosene because - ANSWER- its cheap
NASA's main launch site is in Florida, because of its proximity to the Equator and the
possibility of launching over the Atlantic Ocean. (T/F) - ANSWER- T - Remember that
the closer you are to the Equator, the more help you get from the Earth's rotation in your
attempt to reach orbit. Also, you will want to turn eastward as soon as possible to get
this advantage, and having a launch site on Florida's east coast allows you to fly over
the Atlantic Ocean instead of over inhabited landmasses.
Your rocket is moving eastward around the Earth with the nozzle pointing west. If you
want to drop to a lower orbit, you first need to - ANSWER- pitch 180 degrees and yaw
180 degrees (To drop to a lower orbit you need to SLOW DOWN, right? Right now your
rocket is in a "speed-up" attitude since the nozzle points toward where you've been. So
you need to TURN IT AROUND, back to front. Either a pitch or yaw can do this, but
note that a roll can't - a roll can only turn you upside-down.)
Which type of propellant does not require an ignition system? - ANSWER- hydrazene
(hypergolic)
A launch vehicle weighing 300,000 pounds ignites its engines, which produce 250,000
pounds of thrust. Then the rocket will - ANSWER- just sit on the launch pad, not moving
The Space-X Falcon Heavy rocket launched earlier this year... - ANSWER- was built by
a private company, successfully returned multiple stages to Earth for re-use and could
lift as much weight to orbit as any rocket since the Apollo program
100% CORRECT ANSWERS
Which special place in the Earth's orbit is the Sun located at? - ANSWER- Occupied
Focus
In an elliptical orbit around the Earth, you will have the maximum energy of position
when you're at - ANSWER- Apogee or Apoapsis
Earth's seasons are caused by - ANSWER- the tilt of the Earths rotation axis
During most of the MESSENGER probe's journey from Earth to Mercury, it was -
ANSWER- speeding up with respect to the sun
You are orbiting the Sun and fire your engines at perihelion to SPEED UP. As a result: -
ANSWER- aphelion increases, perihelion stays the same
During a launch, the energy in your fuel is being converted into - ANSWER- heat,
energy of position, energy of motion
For the first few seconds after liftoff, which forces are important? - ANSWER- Gravity
and thrust
You're orbiting the Earth every 2 hours, and then you make a maneuver that increases
your orbital speed. Your NEW orbit will have a period that is - ANSWER- more than 2
hours
You're orbiting the Earth at 7.8 km/sec in a circular orbit. If you slow down to 7.7
km/sec, your new orbit will be circular but will be a bit closer to the Earth. (T/F) -
ANSWER- F - In many situations, if you slow down, you will fall into a lower orbit (but
note, if you started in a circular orbit, the new orbit will be elliptical - that's the first
reason the answer is FALSE here). Also, in this case, you need to remember that 7.8
km/sec is the MINIMUM speed required to be in the lowest possible Earth orbit. If you
slow down a little bit, your new orbit will become an ellipse with the perigee INSIDE THE
EARTH! In other words, your flight will become suborbital and you will fall to the ground.
You're in an elliptical orbit around the Earth. At perigee you increase your speed from
11 km/sec to 12 km/sec. The new orbit will be an elliptical orbit with a higher apogee.
(T/F) - ANSWER- F - In some cases, speeding up will get you to a larger elliptical orbit
with a higher perigee. But remember that 11.2 km/sec is the Earth's ESCAPE SPEED -
beyond this, the orbit changes shape and becomes hyperbolic. No apogee!
Your spacecraft is heading east in an orbit around the Earth. You want to get to a higher
orbit. To make this maneuver you must first make sure that your nozzle is facing -
, ANSWER- West - Another question that tests you on multiple concepts. To get to a
higher (larger) orbit you know you must SPEED UP. This means the nozzle must point
toward where you came from (in this case, the west) in order to achieve a speedup
when you fire the engines. Had the nozzle been pointing east, if you fired the engines
you'd SLOW DOWN and drop to a lower orbit.
When do experience maximum acceleration during a launch? - ANSWER- Just before
burnout
The period of the Earth-Mars Hohmann transfer orbit is 16 months. It is therefore
possible to get to Mars by a Hohmann transfer orbit in - ANSWER- 8 months
When you are many millions of kilometers away from any planet, moon, asteroid, or
comet, then you are not in orbit around anything at all. (T/F) - ANSWER- F - As long as
you're within the Solar System, in this case you'll be orbiting the Sun. Even though the
Sun may also be very far away from your location, it's so massive that its gravitational
pull dominates.
For most of the journey from Earth to Jupiter, you'll measure your velocity with respect
to - ANSWER- the center of the Sun
Russia fuels its rockets with kerosene because - ANSWER- its cheap
NASA's main launch site is in Florida, because of its proximity to the Equator and the
possibility of launching over the Atlantic Ocean. (T/F) - ANSWER- T - Remember that
the closer you are to the Equator, the more help you get from the Earth's rotation in your
attempt to reach orbit. Also, you will want to turn eastward as soon as possible to get
this advantage, and having a launch site on Florida's east coast allows you to fly over
the Atlantic Ocean instead of over inhabited landmasses.
Your rocket is moving eastward around the Earth with the nozzle pointing west. If you
want to drop to a lower orbit, you first need to - ANSWER- pitch 180 degrees and yaw
180 degrees (To drop to a lower orbit you need to SLOW DOWN, right? Right now your
rocket is in a "speed-up" attitude since the nozzle points toward where you've been. So
you need to TURN IT AROUND, back to front. Either a pitch or yaw can do this, but
note that a roll can't - a roll can only turn you upside-down.)
Which type of propellant does not require an ignition system? - ANSWER- hydrazene
(hypergolic)
A launch vehicle weighing 300,000 pounds ignites its engines, which produce 250,000
pounds of thrust. Then the rocket will - ANSWER- just sit on the launch pad, not moving
The Space-X Falcon Heavy rocket launched earlier this year... - ANSWER- was built by
a private company, successfully returned multiple stages to Earth for re-use and could
lift as much weight to orbit as any rocket since the Apollo program
