Physics 1A Winter 2009: Makeup Final
Version A
1
Closed book. No work needs to be shown for multiple-choice questions.
1. A wheel initially has an angular velocity of 40 rad/s but it is slowing at a rate of 2.0 rad/s2
until it comes to a stop. By the time it stops it will have turned through:
(a) 80 rad.
(b) 160 rad.
(c) 200 rad.
(d) 300 rad.
-> (e) 400 rad.
2. What centripetal acceleration does an 40 kg person experience when seated 16 m from the
center of a merry-go-round whose angular speed is 0.50 rad/s?
(a) 20 m/s2.
(b) 10 m/s2.
-> (c) 5 m/s2.
(d) 30 m/s2.
(e) 0.1 m/s2.
3. Three identical massless rods are each acted on by two or more forces, all perpendicular to
the rods and all equal in magnitude (with a force of magnitude F). As you learned in Quiz 5,
none of these rods is in static equilibrium. Now imagine that you can eliminate one of the
fources on each rod. Which of the rods can be brought into static equilibrium? Choose one
of the following statements below.
rod 1
F
rod 2
F
rod 3
F
F
F
F
F
F
(a) Rod 1.
(b) Rod 2.
(c) Rod 3.
(d) All of these three rods can be in static equilibrium if one of the forces on each is
eliminated.
-> (e) None of the three rods can be brought into static equilibrium by eliminating just
one of the forces acting on it.
4. Mitch throws a 100 g lump of clay at a 500 g target, which is at rest on a horizontal surface.
After impact, the target, including the attached clay, slides 2.1 m before stopping. If the
03.03.08
Physics 1A Winter 2009: Makeup Final
Version A
2
coefficient of kinetic friction between the target and the surface is µk = 0.50, find the speed of
the clay before impact.
a. 4.5 m/s.
b. 12 m/s.
-> c. 27 m/s.
d. 36 m/s.
e. 5.0 m/s.
5. A 60kg woman stands in the middle of a frozen pond of radius 10m. She is unable to get to
the other side because of a lack of friction between her shoes and the ice. To propel herself,
she throws a 1.2kg backpack horizontally towards the south shore at a speed of 5m/s. How
long does it take her to reach the north shore?
a. 30s
b. 60s
-> c. 90s
d. 120s
e. 150s
6. A ball of mass 10 kg initially moves with a speed of 1.5 m/s in the +x direction. It then hits
the wall and bounces back with the same speed in the in the –x direction. What was the
change in momentum of the ball?
-> a. –30 kg(m/s).
b. –15 kg(m/s).
c. 0 kg(m/s).
d. +15 kg(m/s).
e. +30 kg(m/s).
7. A car with mass M traveling at speed V has kinetic energy KE. What is the kinetic energy of
a second car that has twice the mass and half the speed of the first car?
-> a. 0.5 KE
b. 2 KE
c. 4 KE
d. 8 KE
e. 0.25 KE
8. A 20-N crate starting at rest slides down a rough 5.0-m long ramp, inclined at 25° with the
horizontal. 20 J of energy is lost to friction. What will be the speed of the crate at the bottom
of the incline?
a. 0.98 m/s
b. 1.9 m/s
c. 3.2 m/s
-> d. 4.7 m/s
e. 6.4 m/s
03.03.08
Physics 1A Winter 2009: Makeup Final
Version A
3
9. An outfielder throws a 0.150 kg baseball at a speed of 40.0 m/s at an initial angle of 30.0o
with respect to the vertical. What is the kinetic energy of the baseball at the highest point of
its motion?
a. zero
b. 120 J
-> c. 30.0 J
d. 52.0 J
e. 90.0 J
10. Awoman at an airport is towing her 20.0kg suitcase at a constant speed by pulling on a strap
at an angle theta with respect to the vertical. She pulls on the strap with a 35.0N force, and the
friction force on the suitcase is 20.0N. What angle does the strap make with the vertical?
a. 5 degree
b. 15 degree
c. 25 degree
-> d. 35 degree
e. 55 degree
11. Two blocks are in contact on a frictionless surface., sitting horizontally next to each other.
You apply a force of 3.2N to block 1 such that it pushes against block two. Mass of block 1 =
3.2kg. Mass of block 2 = 1.2 kg. What is the magnitude of the force between the two blocks?
-> a. 1N
b. 2N
c. 3N
d. 4N
e. 5N
12. A fully loaded 747 jetliner has a mass of 3.6 10^5 kg. It's four engines provide a thrust (orce)
of 7.7 10^5 N. How long a runway is needed for a 747 to achieve take-off speed of 310km/h ?
a.
b.
c.
d.
e.
1000m
1500m
1800m correct
2000m
2500m
13. A car drives North at 40miles/h for 10min, then turns East and goes 5.0 min at 60 miles/h.
Finally, it goes Southwest at 30miles/h for 6.0 min. How far away is the car at the end from the
place it started? (1st Hint: I'm asking for the distance "as the crow flies") (2nd Hint: Define a
coordinate system, and use vector addition.)
a. 1mile
b. 2miles
c. 5miles correct
03.03.08
Physics 1A Winter 2009: Makeup Final
Version A
4
d. 10 miles
e. 20 miles
14. In 1996, Josia Thugwame from South Africa won the Olympic Marathon, completing the 26
miles and 385 yard course in 2h 12min and 36s. What was his average speed?
a. 0.5m/s
b. 1m/s
-> c. 5m/s
d. 10m/s
e. 20m/s
15. The density of bubble gum is about 1g per cubic cm. You blow an 8g wad of gum into a
bubble with a 10cm diameter. What is the thickness of the bubble's skin?
a. 0.01mm
b. 0.1mm
-> c. 0.2mm
d. 0.5mm
e. 1.0mm
16. What is the units of Pascal?
a)
b)
c)
d)
e)
N/m
kg/(m s2) correct
kg m/ s2
kg/(m2 s2)
none of the above
17. Water enters a house through a pipe with an inside diameter of 2cm at an absolute pressure of
400 kPa. A 1cm diameter pipe leads from the ground floor (where the water piping enters the
house) to the second floor bathroom, 5m above. When the flow speed at the 2cm diameter inlet is
1.5m/s, find the water pressure in the bathroom.(density of water = 1000kg/m3)
a. 1,000 Pa
b. 20,000 Pa
-> c. 300,000 Pa
d. 400,000 Pa
e. 500,000 Pa
18. The water in a garden hose is at a gauge pressure of 140kPa, and is moving at negligible
speed. The hose terminates in a sprinkler system consisting of many small holes. What is the
maximum height reached by the water from the emerging holes? (The density of water is
1000kg/m3 )
a. 5m
03.03.08
Physics 1A Winter 2009: Makeup Final
Version A
5
b. 10m
-> c. 15m
d. 20m
e. 25m
19. A 200kg flat bottomed boat floats in fresh water, which has density of 1000kg/m3. Assuming
that the base of the boat is 1.42m wide and 4.53m long. To what height is the boat submerged
when it carries three passengers whose total mass is 269kg?
a.
b.
c.
d.
e.
03.03.08
1cm
10cm correct
20cm
30cm
40cm