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Chapter 4
Review questions
4, 8, 16, 29, 31, 32, 34
Plug and Chug
2, 4, 6, 8, 10
Ranking
2, 4
Exercises
8, 20, 28, 30, 38, 44, 58
Chapter 5
Review questions
10, 12, 20, 22
Plug and Chug
4
Ranking
2, 4
Exercises
12, 24, 28, 34, 38, 44, 50
Problems
2, 4
State Kepler’s three laws and derive Kepler’s third law using Newton’s gravitational force equation and
the equation for the centripetal force?
Briefly describe Galileo’s two key experiments and describe the results with an equation.

°
= 10(
√
2)m/s
2m
4.25m
45
o
A shot putter throws a 4kg shot at a 45
o
angle upward with a two-dimensional velocity of 10(
√
2) m/s.
The shot leaves his hand at a height of 2m and takes a projectile path off of a cliff and lands on a
platform located 4.25m below ground level (Hint: Cos45
o
= Sin45
o
= (1/
√
2),
√
(2.25) = 1.5)
Calculate the horizontal distance to the platform. (Hint: You need to calculate the time to the peak
height and then the time to platform.)
Draw a velocity vs. time graph with zero acceleration.
Draw a velocity vs. time graph with constant-positive acceleration.
Draw the distance vs. time graph, corresponding to the previous graph, and draw a line representing the
average velocity.
Use the velocity vs. time graph to calculate the acceleration and an equation of motion to calculate the
distance.

CHAPTER 4
NEWTON ' S SE CON D LAW OF MOTION
61
Volume
The quantity ofspace an object occupies.
Newton's second law
The acceleration of an object is directly
proportional to the net force acting on the object, is in
the direction of the net force, and is inversely proportional
to the mass of the object.
Newton
The SI unit of force. One newton (symbol N) is the
force that will give an object of mass
1
kg an acceleration
of 1
m/s' .
SUMMARY
OF
EQUATIONS
Weight
=
mg
.
Fner
AcceleratIon:
a
=
--
m
Force
=
ma
REV I
EW
QUESTIONS
Force Causes Accelerati n
1. Is acceleration proportional to net force, or does accelera-
tion equal net force?
Friction
2.
How does friction affect the net force on an object?
3.
How great is the force of friction compared with your
push on a crate that doesn't move on a level floor?
4.
As
you increase your push, will friction on the crate
increase
also?
5.
Once the crate is sliding, how hard do you push to keep it
moving at constant velocity?
6.
Which is normally greater, static friction or sliding fric-
tion on the same object?
7. How does the force offriction for a sliding object vary
with speed?
B.
Slide a block on its widest surface, then tip the·block so it
slides on its narrowest surface. In which case is friction
greater?
9.
Does fluid friction vary with speed? With area of contact?
Mass and Weight
10.
What relationship does mass have with inertia?
11.

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