Transcript Science 8-Chapter 2 Less 2 HD Notes Ansx

Science 8
Chapter 2-The Laws of Motion
Newton’s First Law
Lesson 2
1. What causes an object in
motion to remain in motion?
A. friction
B. inertia
C. gravity
D. velocity
1. What causes an object in
motion to remain in motion?
A. friction
B. inertia
C. gravity
D. velocity
2. Extend Three people push a
piano on wheels with forces of 130
N to right, 150 N to left, and 165 N
to the right. What are the strength
and direction of the net force on the
piano? Draw a diagram.
130 N to the right
165 N to the right
150 N to the left
Force to the right—135 + 160 = 195 N to
the right
Force to the left = 150 N to the left
Net force= 45N to the right
Assess A child pushes down on a
box lid with a force of 25 N. At
the same time, her friend pushes
down on the lid with a force of
30 N. The spring on the box lid
pushes upward with a force of
60 N. Can the children close the
box? Why or why not? Draw a
diagram.
The
spring on
the box
pushes
60 N
upward.
Child
pushes
down
25 N.
Friend
pushes
down
30 N.
25 N + 30 N ? 60 N
25 N + 30 N < 60 N
No, the children can not push the lid
down! Not enough force!
Analyze What is the missing force?
135 N
?N
Net force
25 N
Analyze What is the missing force?
135 N
?N
Net force
25 N
135 N + ? N = 25 N
110 N
To the left or -110 N
5. Use the information in the diagram to
complete the equation and determine the net
force on the object. The reference direction is
“to the right.”
100 N
55 N
____________ N + _________________ N = _________________ N net force
5. Use the information in the diagram to
complete the equation an determine the net
force on the object. The reference direction is
“to the right.”
100 N
55 N
100 N + -55 N = 45 N net force