PHY Ch. 10
An airplane flies at 40 m/s at an altitude of 50 meters. The pilot drops a heavy package which falls to the ground. Where, approximately, does the package land relative to the plane's new position?
beneath the plane
A meteor is captured by earth's gravitational field and goes into elliptical orbit around the earth. Compared to when the meteor is far from the earth, its speed when it is close to the earth is
faster
A "weightless" astronaut in an orbiting shuttle is
like the shuttle, pulled by Earth's gravitation
An object is thrown vertically into the air. Because of air resistance, the time for its descent will be
longer than the ascent time.
Which would require the greater change in the Earth's orbital speed (30 km/s); slowing down so the Earth crashes into the sun, or speeding up so the Earth escapes the sun?
slowing down
A student throws a ball horizontally from the top of a 20 meter tall building. The ball hits the ground 20 m from the building. What was the students pitching speed?
10 m/s
A gun with a muzzle velocity of 100 m/s is fired horizontally from a tower. Neglecting air resistance, where will the bullet be 1 second later?
100 m down range
A projectile is thrown into the air at an angle of 50 degrees and lands on a target that is at the same level at which the projectile started. It will also land on the target if it is thrown at an angle of
40 degrees
Earth satellites are typically more than 100 km high so as to be above the Earth's
atmosphere
A ball is thrown horizontally. After it has left the thrower's hand, what is the acceleration that it experiences ?
1 g downward
A hunter on level ground fires a bullet parallel to the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first?
Both hit at the same time.
An oval path that a satellite follows as it orbits the earth. This describes ____
Ellipse
A projectile must reach this speed to escape the gravitational pull of the earth. This describes ____
Escape speed
An object is thrown vertically into the air. Because of air resistance, the total height to which the object travels is ___ than the total height it would have travelled if there were no air resistance.
Less than
What prevents satellites such as the space shuttle from falling?
Nothing; they continually fall all around the earth.
A curved path that a projectile follows when under only the influence of gravity (near the earth). This describes ____
Parabola
An object that is moving under the influence of gravity. This describes ____
Projectile
A ball player wishes to determine pitching speed by throwing a ball horizontally from an elevation of 5 m above the ground. The player sees the ball land 20 m down range. What is the player's pitching speed?
about 20 m/s
A pitcher drops a ball. At the same instant, another ball is thrown at an angle of 5 degrees below the horizontal. Which ball will hit the ground first ?
the ball thrown
A hunter on level ground fires a bullet at an angle of 10 degrees above the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first?
the dropped one
A hunter on level ground fires a bullet at an angle of 10 degrees below the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first?
the fired one
What keeps the moon from falling?
the moon is falling around the earth
An object is dropped and freely falls to the ground with an acceleration of 1 g. If it is thrown upward at an angle instead, its acceleration will be
1 g downward
. A small body that orbits a larger celestial body; e.g., the moon orbiting the earth. This describes ____
Satellite
From Earth, one satellite appears to overtake another. The faster satellite is
lower
A rocket coasts in an elliptical orbit about the Earth. To attain escape velocity using the least amount of fuel in a brief firing time, should it fire off at the apogee, or at the perigee? (Hint: Let "Fd change in KE" guide your thinking.)
perigee, where it is closest and fastest
Acceleration is greater for a satellite when it is at the
perigee.
The radial velocity of an Earth satellite is its velocity
perpendicular to the surface of the Earth
