Download Chapter 18 Standardized Test Preparation

Chapter 18
Standardized Test Preparation
Benchmark and Reading Check Q & A:
1. Pg 563: How does gravity differ from friction?
Answer to Benchmark Check:
Unlike friction, gravity can act between objects that are
not touching.
2. Pg 564: How does mass affect gravitational force?
Answer to Reading Check:
Gravitational force increases as mass increases. (Note:
Gravitational force increases as the mass of one or both
of the objects increases.)
3. pg 566: Name 2 forces that act at a distance:
magnetic, and electric, OR gravity.
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Chapter 18
Standardized Test Preparation
Ch. Review Q & A (570-571):
1. Opposes motion between surfaces that are touching.
 Friction
2. The ________ is the unit of force.
 Newton
3. _________is determined by combining forces.
 Net force
4. Acceleration is the rate at which ________ changes.
 velocity
5. If a student rides her bicycle on a straight road and
does not speed up or slow down, she is traveling with a
 b. constant velocity.
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Chapter 18
Standardized Test Preparation
6. A magnet can exert a magnetic force on materials
containing iron. Which of the following is an example
of a magnetic force acting at a distance?
c. Magnets hold papers on refrigerator doors.
7. A hurricane is heading toward Florida. What information
do you need to determine when the hurricane will
strike the coast?
d. the hurricane’s position, speed, and direction of
motion
8. The gravitational force between 1 kg of lead and Earth
is the gravitational force between 1 kg of marshmallows
and Earth.
c. equal to
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Chapter 18
Standardized Test Preparation
9. Which of the following is a measurement of velocity?
 c. 55 m/h south
10. Describe the relationship between motion and a
reference point.
Motion occurs when an object changes position over time
relative to a reference point (an object or location that
appears to stay in place).
11. How is it possible to be accelerating and traveling at a
constant speed?
A change in direction alone causes acceleration to occur.
Thus, no change in speed is necessary for acceleration to
occur.
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Chapter 18
Standardized Test Preparation
Math Skills:
12. A kangaroo hops 60 m to the east in 5 s. Use this
information to answer the following questions:
a. What is the kangaroo’s average speed?
 12 m/s
b. The kangaroo stops at a lake for a drink of water and
then starts hopping again to the south. Each second, the
kangaroo’s velocity increases 2.5 m/s. What is the
kangaroo’s acceleration after 5 s?
 2.5 m/s2 south
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Chapter 18
Standardized Test Preparation
Applying Concepts:
13. Your friend asks to help move some boxes. One box is
so heavy that you must push it across the room rather than
lift it. How could you reduce friction to make moving
the box easier?
All reasonable answers. Sample answer: Use a handcart
or dolly to take advantage of rolling kinetic friction, or polish
the floor to reduce sliding kinetic friction.
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Chapter 18
Standardized Test Preparation
Analyzing Ideas:
14. Consider the scientific meaning of the word
acceleration and the use of the term accelerator when
talking about a car’s gas pedal. How can these meanings
lead to confusion?
Sample answer: A driver uses a car’s gas pedal, which
is called the accelerator, to increase the
car’s speed. This use of the term accelerator may cause
confusion by leading you to think that acceleration means
only “speeding up.” However, the scientific meaning of the
term acceleration includes slowing down and changing
direction. (So, a car’s gas pedal is not the only device in
the car that causes acceleration—the steering wheel could
be called an accelerator, too!)
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Chapter 18
Standardized Test Preparation
Identifying Relationships:
15. Explain why airplane pilots should know wind velocity
as well as wind speed during a flight.
It is helpful for pilots to know wind velocity because
velocity includes direction. Pilots need to know the wind’s
speed and direction so that they will know whether the wind
is blowing in the same direction that the plane is flying
(which could increase the plane’s resultant velocity and
lead to an earlier arrival time) or in a direction that differs
from the direction in which the plane is flying (which might
lead to a later arrival).
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