Ch 5 study guide 2014

Ch 5 study guide 2014
True/False
Indicate whether the statement is true or false.
____
1. Balanced forces acting on an object cause the object to accelerate.
____
2. Gravity causes all falling objects to accelerate at a rate of 98 m/s2.
____
3. Friction is a force that encourages motion between two surfaces that are touching each other.
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
____
4. The greater an object's mass, the weaker the gravitational force on it. _________________________
____
5. When a ball is dropped, it falls down due to the force of friction. _________________________
____
6. Pushing a box up a hill, you have to overcome static friction. _________________________
____
7. A box doesn't move when you push it because of static friction. _________________________
____
8. Force is the ability to change motion. _________________________
____
9. Weight is a force due to gravity pulling on any object with mass. _________________________
____ 10. Tension is a contact force. _________________________
____ 11. A moving object slows to a stop because of compression. _________________________
____ 12. The greater the force squeezing two surfaces together, the smaller the friction force.
_________________________
____ 13. Lubrication reduces the friction between machine parts. _________________________
____ 14. A zero net force causes an acceleration. _________________________
____ 15. If an object is at rest, the net force on it must be unbalanced. _________________________
Completion
Complete each statement.
16. ____________________ friction is the friction between two surfaces that are not moving past each other.
Select the correct term to complete each sentence. There are extra terms in the list.
greater than
less than
equal to
vector
tension
newton
net
scalar
compression
pound
equilibrium
friction
normal
kilogram
free-body
17. If you traveled to Mars, your mass would be _________________________ than your mass on Earth.
18. Force is a(n) ____________________ because it has both an amount and a direction.
19. A force that resists the motion of objects or surfaces as they move over one another is called
____________________.
20. The force exerted by a surface on an object that is pressing on it is the ____________________ force.
21. The force which is the sum of all forces acting on a object is called ____________________ force.
22. A diagram shows all the forces acting on an object is a _________________________ diagram.
23. A push or pull is an example of a(an) ____________________.
24. The type of force measured by a grocery store spring scale is ____________________.
25. The sum of all the forces acting on an object is called the _________________________.
26. If the forces acting on an object produce a net force of zero, the forces are called
_________________________.
27. It usually takes more force to start an object sliding than it does to keep an object sliding because static
friction is usually ____________________ than sliding friction.
28. The two forces acting on a falling object are gravity and _________________________.
29. The force of gravity acting on an object is the object’s ____________________.
30. The universal force that is most effective over the longest distances is ____________________.
Short Answer
31. Explain how the same object could weigh 50 pounds on Earth and 8.3 pounds on the Moon.
32. List 3 ways of reducing friction.
33. List 3 ways in which friction is useful.
34. What does it mean when the net force on an object is zero?
Problem
35. The diagram below represents an object moving to the right with a constant velocity.
What is the value of force F?
36. The mass of a newborn baby is 4.2 kilograms. What is the baby’s weight? (The acceleration due to gravity at
Earth’s surface is 9.8 m/s2.) Show your work.
Ch 5 study guide 2014
Answer Section
TRUE/FALSE
1. ANS:
STA:
2. ANS:
STA:
3. ANS:
STA:
F
PTS: 1
PS.B.8.3
F
PTS: 1
ES.A.8.2 | PS.B.8.2 | PS.B.8.3
F
PTS: 1
PS.B.8.3
DIF: B
OBJ: 1/1
DIF: B
OBJ: 3/1
DIF: B
OBJ: 2/1
MODIFIED TRUE/FALSE
4. ANS: F, stronger
PTS: 1
5. ANS: F, gravity
DIF: B
OBJ: 6/2
STA: ES.A.8.2 | PS.B.8.3
PTS: 1
6. ANS: F, sliding
DIF: B
OBJ: 6/2
STA: ES.A.8.2 | PS.B.8.3
DIF: B
OBJ: 2/1
PTS: 1
STA: PS.B.8.3
DIF: B
PTS: 1
DIF:
basic
PTS: 1
DIF:
basic
PTS: 1
DIF:
basic
DIF:
basic
7.
8.
9.
10.
11.
PTS:
ANS:
OBJ:
ANS:
REF:
ANS:
REF:
ANS:
REF:
ANS:
1
T
2/1
T
section 5.1
T
section 5.1
T
section 5.1
F, friction
STA: PS.B.8.3
PTS: 1
12. ANS: F
larger
greater
DIF: basic
REF: section 5.2
PTS: 1
13. ANS: T
REF: section 5.2
14. ANS: F
unbalanced
nonzero
DIF: basic
REF: section 5.2
PTS: 1
PTS: 1
15. ANS: F
DIF: basic
REF: section 5.3
balanced
zero
PTS: 1
DIF: basic
REF: section 5.3
PTS: 1
17. ANS: equal to
DIF: B
OBJ: 2/1
PTS: 1
18. ANS: vector
DIF: basic
REF: section 5.1
PTS: 1
19. ANS: friction
DIF: basic
REF: section 5.1
PTS: 1
20. ANS: normal
DIF: basic
REF: section 5.2
PTS: 1
21. ANS: net
DIF: basic
REF: section 5.3
PTS: 1
22. ANS:
free-body
free body
DIF: basic
REF: section 5.3
PTS: 1
23. ANS: force
DIF: basic
REF: section 5.3
PTS: 1
24. ANS: weight
DIF: L1
OBJ: 12.1.1
PTS: 1
25. ANS: net force
DIF: L2
OBJ: 12.1.1
PTS: 1
26. ANS:
balanced forces
balanced
DIF: L1
OBJ: 12.1.2
PTS: 1
27. ANS:
greater
larger
DIF: L2
OBJ: 12.1.2
PTS: 1
DIF: L2
OBJ: 12.1.3
COMPLETION
16. ANS: Static
STA: PS.B.8.3
28. ANS:
air resistance
drag
PTS: 1
29. ANS: weight
DIF: L1
OBJ: 12.1.4
PTS: 1
30. ANS: gravity
DIF: L1
OBJ: 12.2.3
PTS: 1
DIF: L2
OBJ: 12.4.3
SHORT ANSWER
31. ANS:
Weight depends on gravity. The strength of gravity depends on the size of the planet. The Moon is much
smaller than the Earth, and its gravity is only 1/6 as strong.
PTS: 1
DIF: intermediate REF: section 5.1
32. ANS:
Answers will vary. Example answers include:
Using lubricants
using ball bearings
separating surfaces with a cushion of air.
PTS: 1
DIF: basic
REF: section 5.2
33. ANS:
Answers may vary. Example answers include:
Brakes increase friction to help stop bikes.
Grooved tread on tires increases friction to help tires grip the road in wet weather.
Cleats on shoes help your foot provide more force to the ground and keep you from slipping.
PTS: 1
DIF: basic
REF: section 5.2
34. ANS:
The object is in equilibrium and the forces are balanced. The object is not accelerating. it may be either at rest
or moving at a constant velocity.
PTS: 1
DIF: intermediate
REF: section 5.3
PROBLEM
35. ANS:
In order for the box to move at a constant velocity, it must be in equilibrium with a net force of zero.
Therefore, the force F pulling to the left must balance the 6 N force pulling to the right.
F=6N
PTS: 1
36. ANS:
DIF: advanced
REF: section 5.3
PTS: 1
DIF: L2
OBJ: 12.2.3