Unit 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
According to Kepler's laws, the paths of planets about the sun are
ellipses
A ball is thrown into the air at some angle. At the very top of the ball's path, its velocity is
entirely horizontal
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its horizontal component of velocity
remains unchanged
A projectile is fired vertically from the surface of the Earth at 5 km/s. The projectile will
rise and fall back to the Earth's surface
A projectile is fired into the air at an angle of 50 degrees with the ground 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 fired at an angle of
40 degrees
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
An Earth satellite is in an elliptical orbit. The satellite travels fastest when it is
nearest the Earth
Earth satellites are typically more than 100 km high so as to be above the Earth's
atmoshphere
You're in an airplane that flies horizontally with speed of 460 m/s when an engine falls off. Neglecting air resistance, assume it takes 37s for the engine to hit the ground. If the airplane somehow continues to fly as if nothing had happened, what is the distance between the engine and the airplane at the moment the engine hits the ground?
0
Throw an object upward at a 45 degree angle. With no gravity it will follow a straight-line path. But because of gravity, at the end of 1, it is
About 5 m below the straight line
Where does a satellite in a circular orbit have the greatest kinetic energy?
At the point closest to the planet
A satellite has its greatest potential energy when it is at the perigee.
False
How far must one travel to get away from the Earth's gravitational field?
Forget it; you can't travel far enough
What prevents satellites such as the space shuttle from falling?
Nothing; they are continually falling as they orbit the Earth.
The speed of a satellite in an elliptical orbit is _____.
not constant
The tangential velocity of an Earth satellite is its velocity
parallel to the surface of the Earth
A satellite close to Earth will orbit it in about 90 minutes.
true
The place in a satellite's orbit where the satellite is farthest from Earth is the apogee.
true
Pioneer 10 was able to escape the solar system by
using Jupiter as a "slingshot"
The Earth is closer to the sun in January than in July, which accounts for the fact that the highest high tides in the northern hemisphere occur in
winter
In the absence of air resistance, the angle at which a thrown ball will go the farthest is
45 degrees
A projectile is launched vertically upward at 50 m/s. If air resistance is negligible, its speed upon returning to its starting point is
50 m/s
A satellite near the Earth makes a full circle in about an hour and a half. How long would a satellite located as far away as the moon take to orbit the Earth?
about 28 days
Inside a freely falling elevator, there would be no
apparent weight for you
An engineer is designing satellites for a cell phone company. Satellites can be used to relay cell phone signals because they are free from Earth's gravity.
false
The sum of a satellite's kinetic energy and potential energy varies as the satellite orbits a planet.
false
An Earth satellite is simply a projectile
freely falling around the earth
The Early Bird communication satellite hovers over the same point on Earth's equator indefinitely. This is because
its orbital period is 24 hours
Minimal orbital speed about the Earth is about 8 km/s. Minimal orbital speed about the moon would be
less than 8 km/s
Acceleration is greater for a satellite when it is at the
perigee
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its vertical component of velocity
remains unchanged
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 fired one
A period of a satellite is defined as _____.
the time for a satellite to make one complete revolution around Earth
The horizontal component of a projectile's velocity is independent of
the vertical component of its velocity
