
1.


The difference
between speed and velocity is that ______.
Your Answer:

velocity
also includes a direction. 


Correct. Velocity
describes speed in a particular direction. 

2.


The acceleration
of gravity on Earth is approximately 10 m/s^{2 }(more
precisely, 9.8 m/s^{2}). If you drop a rock from a tall
building, about how fast will it be falling after 3 seconds?
Your Answer:

10 m/s^{2}


Correct Answer:

30 m/s



This answer does not have
units of speed. 

3.


Suppose you lived
on the Moon. Which of the following would be true?
Your Answer:

Your
mass would be less than your mass on Earth, but your weight would be
the same as it is on Earth. 

Correct Answer:

Your
weight would be less than your weight on Earth, but your mass would be
the same as it is on Earth. 


Incorrect. 

4.


In which of the
following cases would you feel weightless?
Your Answer:

while
accelerating downward in an elevator 

Correct Answer:

while
falling from a roof 


Your
weight would be reduced when the elevator accelerates downward, but you
would not be weightless unless the cable broke and you were in
freefall. 

5.


Which statement
must be true in order for a rocket to travel from Earth to another
planet?
Your Answer:

It must
attain escape velocity from Earth. 


Correct. 

6.


Momentum
is defined as ______.
Your Answer:

force
times velocity 

Correct Answer:

mass
times velocity 


Sorry. 

7.


Which of the
following statements is NOT one of Newton's Laws of Motion?
Your Answer:

For any
force, there always is an equal and opposite reaction force. 

Correct Answer:

What
goes up must come down. 


This is Newton's third
law of motion, but the question asked for a statement that is NOT one
of Newton's laws. 

8.


Newton's Second
Law of Motion tells us that the net force applied to an object equals
its:
Your Answer:

mass
times energy. 

Correct Answer:

mass
times acceleration. 


Sorry. 

9.


When a spinning
ice skater pulls in his arms, he spins faster because ______.
Your Answer:

his
angular momentum must be conserved, so reducing his radius must
increase his speed of rotation. 


Correct. 

10.


According
to the universal law of gravitation, if you triple the distance between
two objects, then the gravitational force between them will ______.
Your Answer:

decrease
by a factor of 3. 

Correct Answer:

decrease
by a factor of 9. 


Sorry. 

11.


What is the
difference between a bound orbit and an unbound orbit around the Sun?
Your Answer:

An
object on a bound orbit follows the same path around the Sun over and
over, while an object on an unbound orbit approaches the Sun just once
and then never returns. 


Correct. 

12.


Why is Newton's
version of Kepler's third law so useful to astronomers?
Your Answer:

It can
be used to determine the masses of many distant objects. 


Correct. 

13.


Approximately
where is it currently high tide on Earth?
Your Answer:

Anywhere
that ocean water laps upon the shore. 

Correct Answer:

On
the portions of the Earth facing directly toward the Moon and on the
portion of the Earth facing directly away from the Moon. 


Sorry. 

14.


Which of the
following facts CANNOT be traced to effects of tidal friction?
Your Answer:

High
tides on Earth come approximately 12 hours apart. 


True,
but this is a result of the Earth's current rate of rotation, not of
tidal friction (although the rate of rotation has been affected by
tidal friction over billions of years. 

15.


If the Moon did
not have a synchronous rotation, then
Your Answer:

we
would no longer have tides on Earth. 

Correct Answer:

we
would no longer always see nearly the same face of the Moon. 


Tides would still be
produced by the Moon. 

16.


Suppose
that a lone asteroid happens to be passing Jupiter on an unbound orbit
that keeps it well above Jupiter's atmosphere and far from all of
Jupiter's moons. Which of the following statements would be true?
Your Answer:

The
asteroid's orbit around Jupiter would not change, and it would go out
on the same unbound orbit that it came in on. 


Correct. Orbits cannot
change spontaneously. 

17.


Newton showed
that Kepler's laws are ______.
Your Answer:

natural
consequences of the law of universal gravitation. 


Correct. 