Physics 101/102 - Spring 2012
QUIZ 2
25 pts (30 possible)
Name _____________________
Date ______________________
Section
101
102
All the previously agreed to rules and specifications still apply, namely no scratch outs, show all your
work, especially the physics as necessary, numbers alone will count little if any at all, don’t use a value
for something unless it is given or you show where it comes from, just indicate only answers for multiple
choice and somehow show what you intend as your answer for problems.
1.
Consider drops of water dripping from a faucet at a constant rate. As the drops fall, they
a. get closer together
b. get farther apart
c. remain at a relatively fixed distance from one another
(2-pnt)
2.
At one instant an object is moving up without air resistance at 10 m/s. Two seconds later its
velocity is about
(2-pts)
a. 10 m/s
b. 15 m/s
c. 20 m/s
d. -15 m/s
e. -10 m/s
3.
Which has zero acceleration? An object
a. at rest
b. moving at constant velocity
c. in mechanical equilibrium
(2-pts)
d. all of these
e. none of these
4.
If you drop a ball in the absence of air resistance, it accelerates downward at 9.8 m/s2. If instead you
throw the ball downward, then its acceleration after release is
(2 pts)
a. less than 9.8 m/s2.
b. equal to 9.8 m/s2.
c. greater than 9.8 m/s2.
5.
When a rock thrown straight upwards gets to the top of its path, its
a.
velocity is zero and its acceleration is zero.
b. velocity is zero and its acceleration is about 10 m/sec2.
c.
velocity is about 10 m/sec and its acceleration is zero.
d. velocity is about 10 m/sec and its acceleration is about 10 m/sec2.
e.
none of these.
6.
Consider the picture below. You must correctly answer b in order to get credit for a.
(a) What does the ball "want to do" when the supporting string is cut?
(b) Give the physics reason(s) to support your answer in (a).
7.
If you kick a wall, your foot hurts. This is a good example of
a.
Newton's first law
d. Murphy's law
b. Newton's second law
e.
Stupid's law
c.
Newton's third law
1
(2 pts)
(2 pts)
(3 pts)
(2 pts)
Physics 101/102
QUIZ 2
Spring 2012
8. On which of these hills does the ball roll down with increasing both speed and acceleration along the
path? Just circle the letter of the figure for the answer. You do not have to explain why.
(2 pts)
A
B
C
Show all your work, physics first.
9.
You see a ball drop from rest from the top of a building and you notice it falls past five windows as
you count very quickly to two. How many windows would the ball have fallen past if you had
counted at the same cadence to four? Assume free fall and justify your answer.
(5 pts)
10.
A DC-10 jumbo jet has a total mass of 30,000 kg and has three engines of 1,000 kg each. Each
engine developes a thrust of 30,000N.
(a) What physics law(s) or principle(s) will you use to find its acceleration in takeoff?
(4 pts)
(b)
OK, what is the value of the acceleration?
2
(2 pts)