Download Fall Final Study Guide Define a scalar quantity. A bicycle rider

Fall Final
Study Guide
1. Define a scalar quantity.
2. A bicycle rider travels 15 km in 1.25 hours. What is the rider's average speed?
12 km/h
3. The slope of the line tangent to the curve on a position-time graph at a specific time is the
__________.
instantaneous velocity
4. In order to convert a quantity expressed in one unit into the same quantity in a different
unit, use a(n) __________.
Conversion factor
5. An object that is thrown down towards the ground has an initial velocity ______.
greater than 0 m/s
6. Your textbook is in equilibrium. What can you say about the forces acting on it?
The net force is zero
The acceleration is zero.
7. Newton's third law of motion states that __________.
all forces come in pairs
8. What is the weight of a 225 kg space probe on the moon? The acceleration of gravity
on the moon is 1.62 m/s2.
364 N
9. The force exerted on one surface by another when there is no motion between the
surfaces.
static friction
10. What is the y-component of a 95.3 N force that is exerted at 57.1o to the horizontal?
80.0 N
11. The perpendicular contact force exerted by a surface on another object.
normal force
12. The tendency of an object to resist change is _______.
inertia
13. Normal force is a ______.
contact force
14. “k” is the symbol for which prefix?
kilo
15. 1 millimeter is equal to how many meters?
10-3 m.
16. 86.2 cm is equal to how many kilometers?
8.62x10-4 km
17. Tim has a problem to do involving time, distance, and velocity, but he has forgotten the
formula. The question asks him for a measurement in seconds, and the numbers that are
given have units of m/s and km. What could Tim do to get the answer in seconds?
Divide the km by the m/s, then multiply by 1000.
18. The position-time graph below is describing what kind of velocity?
constant velocity
19. An object experiences an acceleration when ______________.
it changes direction and/or when it changes speed only
20. What are the dimensions of acceleration (not the units of acceleration)
L/T2
21. A car travels in the negative x-direction and has a negative acceleration. The car is
________.
speeding up
22. An object in free fall has what characteristics?
has constant acceleration
23. An object is thrown into the air and then caught at the same height upon landing. The
object:
has an initial velocity equal to the final velocity and has a net displacement of zero.
24. The motion diagram below is describing _________________?
Constant acceleration
25. A 1.60 m tall girl throws a football at an angle of 41o from the horizontal and at an initial
velocity of 9.40 m/s. How far away from the girl will it land?
10.5 m
26. A dragonfly is sitting on a merry-go-round 2.8 m from the center. If the tangential
velocity of the ride is 0.89 m/s, what is the centripetal acceleration of the dragonfly?
0.28 m/s2
27. A 1000 kg car enters an 80.0 m radius curve at 20.0 m/s. What centripetal force must be
supplied by friction so the car does not skid?
5.0x103 N
28. Two satellites are in orbit around a planet. One satellite has an orbit radius of 8.0x106 m.
The period of rotation for this satellite is 1.0x106 s. The other satellite has an orbit of
2.0x107 m. What is this satellite’s period of rotation?
4.0x106 s
29. A moon revolves around a planet with a speed of 9.0x103 m/s. The distance from the
moon to the center of the planet is 5.4x106m. What is the orbital period of the moon?
1.2π x 103 s
30. The acceleration of an object in uniform circular motion is called __________.
centripetal acceleration
31. You accidentally throw your car keys horizontally at 5.0 m/s from a cliff 45 m high. How
far from the base of the cliff should you look for your keys?
15 m
32. Two balls have their centers 3.0 m apart. One ball has a mass of 2.7 kg. The other has a
mass of 4.5 kg. What is the gravitational force between them? Assume G = 6.67×10-11
N·m2/kg2.
9.0x10-11 N
33. A satellite orbits Earth 5.00×102 km above its surface. What is its period?
1.58 h
34. According to Kepler's laws, what happens to planets’ velocities when they move further
away from the sun?
Planets move faster when they are closer to the Sun and slower when they
are farther away
35. According to Newton's law of universal gravitation in the case of a planet near the Sun,
which of the following would cause the attractive force to be quadrupled?
quadruple the mass of the planet
36. A 930-kg car traveling 56 km/h comes to a complete stop in 2.0 s. What is the force
exerted on the car during this stop?
-7.2x103 N
37. Convert 1.45 km to meters.
1.45x103 m
38. __________ describes the degree of exactness in a measurement.
Precision
39. In the particle model, the __________ of the object are (is) ignored.
internal motions
40. __________ defines the distance and direction between two positions.
Displacement
41. Convert 57.7 kg to grams.
57,700 g
42. Express the quantity 0.00000095 kg in scientific notation.
9.5x10-7
43. What value is calculated by dividing rise by run?
slope of a line
44. In order to use the particle model, the __________ must be __________ moved.
size of the object, much less than the distance
45. To subtract two vectors, __________.
reverse the direction of the second vector and then add them
46. The vector that represents the sum of two vectors is called the __________.
resultant
47. You drive a car for 2.0 h at 60 km/h, then for another 3.0 h at 85 km/h. What is your
average velocity? 75 km/h
48. If a runner maintains a constant speed of 12.0 km/h, how long will it take him to
complete a marathon race of 26.2 miles?
3.52 h
49. What information can you obtain from a velocity time graph?
(acceleration, velocity at a given moment in time, displacement)
50. How are velocity and acceleration related?
(Acceleration is the change in velocity divided by the time interval in which
the change occurs; acceleration is the rate of change of velocity)
51. A ball falling freely to the ground has the following forces acting on it:
gravity, normal, drag force
52. 3.4897 rounded to three significant figures is ________.
3.49
53. If 0.20 bushel is 1 dozen apples and a dozen apples has a mass of 2.0 kg., what is the
mass of 0.50 bushel of apples?
5.0 kg
54. The prefix centi- means_______.
times smaller than the unit it precedes.
55. Can the velocity of an object change when its acceleration is constant?
(Yes, think of any free falling object. It acceleration is 9.8 m/s2, but its
velocity is constantly changing)
56. If an object’s velocity-time graph is a straight line parallel to the x-axis (the “time” axis),
what can you conclude about the object’s acceleration?
(The object’s acceleration is zero)
57. A car moving north at 8.0×101 turns and travels south at 65 km/h. What are the
magnitude and direction of the change in velocity?
(145 km/h, N to S)
58. How far does a car travel in 30.0 s while its velocity is changing from 50.0 km/h to 80.0
km/h at a uniform rate of acceleration?
(5.4x102 m)
59. A car with a velocity of 30 m/s is accelerated uniformly at the rate of 2.0 m/s2 for 10 s.
What is its final velocity?
(50 m/s)
60. A car is accelerated uniformly at the rate of 0.50 m/s2 for 1.0×1 s. Its final velocity is 23
m/s. What is the initial velocity?
(18 m/s)
61. A 75-kg swimmer steps off a 10.0-m tower. What is the swimmer's velocity on hitting the
water?
(-14.0 m/s)
62. If the net force on an object is zero, the object is ___________.
in equilibrium
63. Is mass a force?
not a force
64. The force exerted by a fluid on the object moving through a fluid is ______.
drag force
65. On Earth, a scale shows that you weigh 490 N. What is your mass?
50 kg
66. A 45 N force is exerted in the upward direction on a 2.0 kg briefcase. What is the
acceleration of the briefcase?
22.5 m/s2
67. A bike rider approaches a hill at a speed of 3.5 m/s. The mass of the bike and rider
together is 77 kg. The rider coasts up the hill. Assuming that there is no friction, at what
height will the bike come to rest?
0.62 m
68. A ball falls freely from rest for 15.0 s. Calculate the ball's velocity after 15.0 s.
(-147 m/s)
69. Can an object change its acceleration without an outside force acting upon it?
(No)
70. True or false? An object at rest has no forces acting upon it. Explain.
(False)
71. The vector sum of two or more forces on an object is called the __________ force.
(net)
72. __________ describes how well the results of an experiment agree with the standard
value.
Accuracy
73. The point at which a line crosses the y-axis is the __________.
y-intercept
74. The standard SI unit of mass is the __________.
kilogram
75. In a tug-of-war, 13 children, with an average mass of 30 kg each, pull westward on a rope
with an average force of 150 N per child. 5 Parents, with an average mass of 60 kg each,
pull eastward on the other end of the rope with an average force of 475 N per adult.
Assuming that the whole mass accelerates together as a single entity, what is the
acceleration of the system?
(0.62 m/s2 E)
76. A race car has a mass of 710 kg. It starts from rest and travels 40.0 m in 3.0 s. The car is
uniformly accelerated during the entire time. What net force is exerted on it?
(6.3x103 N)
77. Poloma hands a 13 kg box to 61 kg Stephanie, who stands on a platform. What is the
normal force exerted by the platform on Stephanie?
(7.3x102 N)
78. A 45 kg child sits on a 3.2 kg tire swing. What is the tension in the rope that hangs from a
tree branch?
(4.7x102N)
79. You walk 30 m south and then 30 m east. Find the magnitude and direction of the
resultant displacement both graphically and algebraically.
(4x101 m 45o east of south)
80. A car moves 65 km due east, then 45 km due west. What is its total displacement?
(2.0x101 km east)
81. A sled of mass 40.0 kg is pulled along flat, snow-covered ground. The static friction
coefficient is 0.28, and the kinetic friction coefficient is 0.08. What force will be needed
to start the sled moving?
(110 N)
82. If you use a horizontal force of 30.0 N to slide a 12.0 kg wooden crate across a floor at
constant velocity, what is the coefficient of friction between the crate and the floor?
(0.255)
83. A force of 40.0 N accelerates a 5.0 kg block 6.0 m/s2 along a horizontal surface. (a) How
large is the frictional force? (b) What is the coefficient of kinetic friction?
(1.0x101 N; 0.20)
84. A crate weighing 562 N is resting on a plane inclined 30.0o above the horizontal. Find the
component of the weight forces that are parallel and perpendicular to the plane.
(parallel = 281 N; perpendicular = 487 N)
85. A 62 kg person on skis is going down a hill sloped at 37o. The coefficient of kinetic
friction between skis and the snow is 0.15. How fast is the skier going 5.0 s after
starting from rest?
(23.6 m/s)
86. In Newton's equation, F = Gm1m2/r2, r is __________.
the distance between the centers of the masses
87. The relationship between the linear and angular velocities is given by:
vt = rω2
88. The product of the force and the position vector is called __________.
torque
89. A child attempts to use a wrench to remove a nut on a bicycle. Removing the nut requires
a torque of 10 N m. The minimum force the child is capable of exerting at a 90o angle is
50 N. What is the length of the wrench the child must use to remove the nut?
0.2 m
90. A ball is launched at 4.5 m/s at 66o above the horizontal. What are the maximum height
and flight time of the ball?
(0.86 m; 0.84 s)