Transcript Document

Unit Combo: Laws of Motion and Fluid Motion
Titanium Tetrachloride produces smoke that does not rise unless picked up by fluid.
If there were no launch pad beneath a NASA
rocket at liftoff, the upward thrust of its engines
would be
1. approximately unchanged
2. approximately half as much
3. approximately zero
Suppose Earth had no atmosphere and a ball were fired from the
top of Mt. Everest in a direction tangent to the ground. If the initial
speed were high enough to cause the ball to travel in a circular
trajectory around Earth, the ball’s acceleration would
1. be much less than g (because the ball doesn’t fall to the
ground).
2. be approximately g.
3. depend on the ball’s speed.
The Moon does not fall to Earth because
1. It is in Earth’s gravitational field.
2. The net force on it is zero.
3. It is beyond the main pull of Earth’s gravity.
4. It is being pulled by the Sun and planets as well
as by Earth.
5. all of the above
6. none of the above
Lab Activity
Graphical calculations of orbital motion.
Questions:
E4.21: To free an Apollo spacecraft from the earth’s
gravity took the efforts of a gigantic Saturn V rocket.
Freeing a lunar module from the moon’s gravity took only
a small rocket in the lunar module’s base. Why was it so
much easier to escape from the moon’s gravity than from
that of the earth?
E4.22: Spacecraft in low earth orbit take about 90
minutes to circle the earth. Why can’t they be made to
orbit the earth in half that amount of time?
Using the rocket equation, calculate and compare the
final rocket velocities for 𝑚𝑓𝑢𝑒𝑙 = 2𝑚𝑟𝑜𝑐𝑘𝑒𝑡 , 4𝑚𝑟𝑜𝑐𝑘𝑒𝑡
and 8𝑚𝑟𝑜𝑐𝑘𝑒𝑡 . Use the fuel exit velocity of 2550 𝑚/𝑠 –
approximately the value for the Rocketdyne F-1 engines
used one the first stage of the Saturn V rocket. Comment
on how the velocity changes each time the fuel mass is
doubled.
Orbit Simulator:
http://phet.colorado.edu/en/simulation/mysolar-system