c.
grams
d.
gravity
e.
none of the above
46. How was the value of G first determined?
a.
by Cavendish, using a torsion balance
b.
by Eötvös, using a torsion balance
c.
via a gedanken experiment
d.
by Newton, watching an apple fall
e.
none of the above
47. If a body were in orbit very near the surface of the earth, its centripetal acceleration would
be
a.
equal to g
b.
smaller than g
c.
larger than g
d.
dependent on its mass
e.
none of the above
48. During the period of one day, the number of high tides at a given point is about
a.
one
b.
two
c.
three
d.
four
e.
none of the above
49. Tides are influenced by
a.
the moon
b.
the sun
c.
the uneven surface of the earth
d.
all of the above
e.
none of the above
50. The sensitive dependence upon initial conditions of the evolution of some physical systems
is a feature of
a.
gravitation
b.
fractals
c.
air resistance
d.
dynamical chaos
e.
quantum mechanics
51. Isaac Newton’s contributions to physics include
a.
the laws of motion
b.
the law of universal gravitation
c.
invention of the calculus
d.
the invention of the reflecting telescope
e.
all of the above
52. Starting from rest, a 20,000 kg aircraft being launched from an aircraft carrier goes from 0
to 90 m/s in 2 seconds. The net force acting on the aircraft is
a.
3,600,000N
d.
450,000 N
b.
1,800,000 N
e.
275,000N
c.
900,000 N
53. An aircraft weighs 1,500 N, its mass is
a.
1,500 kg
c.
153 kg
b.
750 kg
d.
mass cannot be determined
54. Two identical airplanes are executing identical turns around a pylon. One of them is moving
at 200 mph, and the other is moving at 100 mph. The centripetal force acting on the airplane
moving at 200 mph is __________ the value of the centripetal force acting on the airplane
moving at 100 mph.
a.
one quarter
d.
twice
b.
one half
e.
four times
c.
the same as
55. An astronaut in a space suit has a total mass of 143.5 kg and is standing on a scale that reads
in newtons inside an elevator. If the elevator accelerates upward at the rate of 1.8 m/s2 ,
what does the scale read?
a.
703.2 N
c.
882.3 N
b.
1,406.3 N
d.
1,664.6 N
56. A 188 pound astronaut in a training exercise experiences an acceleration of 7.2 g’s. What is
the net force (in Newtons) acting on the astronaut?
a.
1,353.6 N
c.
59,030.5 N
b.
6,023.5 N
d.
13,536 N
MULTIPLE RESPONSE
1. Which of these are SI units?
a.
centimeters
b.
newtons
c.
pounds
d.
seconds
e.
none of the above
2. The net force on the body
a.
is zero
c.
points up
b.
has its largest magnitude
d.
points down
3. The acceleration
a.
is zero
c.
points up
b.
has its largest magnitude
d.
points down
4. The displacement vector from the equilibrium position
a.
is zero
c.
points up
b.
has its largest magnitude
d.
points down
5. If the earth’s mass were suddenly made larger but the moon’s mass stayed the same,
a.
the earth would exert a larger force on the moon
b.
the moon would exert a larger force on the earth
c.
the earth would exert a larger force on the moon but the moon would exert the
same force on the earth as before
d.
none of the above
6. A ball is thrown straight up, and reaches the top of its trajectory, the acceleration
a.
zero
c.
points down
b.
9.8 m/s2
d.
points up
COMPLETION
1. The resistance to relative motion of two bodies in contact with each other is called
__________.
2. The mass of a body on the moon is _______________ the mass of the same body on earth.
3. The weight of a body on the moon is _______________ the weight of the same body on
earth.
4. You push on a block on frictionless ice with a force of 8 N, causing it to accelerate at 2 m/s2.
The mass of the block is __________.
5. Starting from rest, a 2 kg body acquires a speed of 8 m/s in 2 seconds. The net force acting
on the body is __________.
6. You whirl a 2 kg body attached to a 1 meter cord around your head in a nearly horizontal
circle with a speed of 4 m/s. The tension in the cord is _________.
7. A car goes around a curve at 40 m/s. An accelerometer in the car measures the centripetal
acceleration of a 2 kg body in the car to be 8 m/s2. The radius of the curve is __________.
8. You stand on a bathroom scale at the equator and at the north pole. The scale reading at the
equator is _______________ the scale reading at the north pole.
9. You drop a freely falling body at the equator and at the north pole. The acceleration of the
freely falling body at the equator is _______________ the acceleration of the freely falling
body at the north pole.
10. You throw a ball straight up. As the ball is going up, the direction of the velocity and
acceleration point __________.
11. You can tell whether a projectile is going upwards or downwards from the sign of
__________.
12. You are holding your physics book, pushing upwards on it with the palm of your hand. The
reaction to this force is the force on __________ by __________.
13. You are holding your physics book, pushing upwards on it with the palm of your hand. The
reaction to the weight of the book is the force on __________ by __________.
14. As you go higher and higher above the surface of the earth, the weight of a body
__________.
15. As you go higher and higher above the surface of the earth, the mass of a body __________.
16. As you go higher and higher above the surface of the earth, the acceleration of a freely
falling body __________.
17. As the radius of the orbit of an artificial satellite increases, its orbital period __________.
18. The shapes of planetary orbits are __________.
19. A body on the surface of the earth weighs 400 lb. The radius of the earth is about 4,000
miles. If this same body were placed on a 4,000 mile high tower, its weight would be
__________.
20. During the period of one day, the number of high tides at a given location is about
__________.
21. The major influence on the tides is due to __________.
22. The sensitive dependence upon initial conditions of the evolution of some physical systems
is a feature of __________.
23. A car and driver have a total mass of 945 kg. While rounding a curve on a flat road at a
speed of 29 m/s, the net force acting on the car and driver is determined to be 56,767.5 N.
The radius of the curve is__________.
24. An object is dropped from a tall building. The net force acting on the object is the
difference between the object’s _________ and the force of air resistance.
MATCHING
Match each item with the correct statement below.
a.
centripetal force
h.
SI
b.
circle
i.
simple harmonic motion
c.
ellipse
j.
static friction
d.
field
k.
terminal speed
e.
kinetic friction
l.
tides
f.
mass
m.
weight
g.
parabola
1. needed to make an object move in a circle
2. keeps our feet from sliding as we walk
3. keeps our feet from sliding as we walk
4. caused by the moon’s gravitational pull
5. shape of the path of a projectile
6. air resistance is one example
7. the force of air resistance leads to this
8. the force of gravity acting on a body
9. an object hanging from a spring can do this
10. a measure of an object’s resistance to acceleration
Match each item with the correct statement below.
a.
m
f.
m/s
b.
m2
g.
m/s2
c.
m3
h.
N
d.
s
i.
kg
e.
Hz
11. the area of the sheet of paper you are looking at
12. the reading on your watch
13. the speedometer reading on your car
14. your weight
15. the mass of a baseball
16. the force exerted on a baseball by a baseball bat
17. the distance between your school and your home
18. the quantity describing how the speed of your car changes
19. the pitch of a note when a piano key is struck
20. the frequency of a body vibrating at the end of a spring
21. the volume of a 5 lb bag of sugar
22. air resistance
23. static and kinetic friction
24. the quantity that measures the resistance of an object to being accelerated
25. the gravitational pull of the earth on the moon
Match each item with the correct statement below.
a.
zero net force
b.
constant net force in the same direction as velocity
c.
constant net force opposite to velocity
d.
constant net force perpendicular to velocity
e.
net force decreasing with speed
f.
restoring force proportional to displacement
26. motion in a straight line with decreasing speed
27. motion in a straight line with increasing speed
28. motion in a straight line at constant speed
29. motion in a circle
30. a body reaching a terminal velocity
31. a body not moving
32. simple harmonic motion
33. a body falling through air
Match each item with the correct statement below.
a.
increases
c.
stays the same
b.
decreases
34. As an astronaut is being launched into space, the astronaut’s mass
35. As a rocket is being launched into space with a constant force (F), the acceleration
36. As the distance between two objects increases, the gravitational force
37. As the radius of turn being made by an aircraft increases, the centripetal acceleration on the
aircraft
PROBLEM
1. A steel ball has a mass equal to 5 kilograms. What is the ball’s weight?
2. Find your own weight in newtons.
3. A ball rolling down a hill has a constant acceleration of 3 m/s2. If the ball’s mass is 2.5 kg,
what is the net force acting on the ball?
4. A 3,000 kg truck experiences a net force of 2,000 N. What is its acceleration?
5. A certain speed boat weighs 4,900 N. It can accelerate from 0 to 20 m/s in 5 seconds.
(a) What is the mass of the boat?
(b) What is the acceleration?
(c) How large is the net force acting on the boat?
6. A child on a merry-go-round is moving with speed 4 m/s in a circle with radius 2 m. If the
child’s mass is 30 kg, what is the centripetal force?
7. A satellite orbits the earth at a distance of 10,000 miles from the earth’s center. At this
distance the force of gravity on the satellite is 90 lbs.
(a) What would the force on the satellite be if the distance were 5,000 miles instead?
(b) At what distance from the earth’s center would the force on the same satellite be 10 lbs?
8. An aircraft starts at rest and is accelerated at 10 m/s2 for 30 seconds, at which time the
aircraft becomes airborne. What is the distance traveled during the 30 seconds? Assume the
acceleration is constant.