Module 3 “Newton’s Laws of Motion”
ISCI 2002
Barron

This lecture will help you understand:
•
Newton's First Law of Motion
•
Newton's Second Law of Motion
•
Forces and Interactions
•
Newton's Third Law of Motion
•
Vectors

Newton's First Law of Motion
•
The law of inertia:
–
Every object continues in a state of rest or of
uniform speed in a straight line unless acted
on by a nonzero force.

Newton's First Law of Motion
CHECK YOUR UNDERSTANDING
A sheet of paper can be quickly withdrawn from
under a soft-drink can without the can toppling
because
A.
gravity pulls harder on the can than on the
paper.
B.
the can has weight.
C.
the can has inertia.
D.
none of the above

Newton's First Law of Motion
CHECK YOUR ANSWER
A sheet of paper can be quickly withdrawn from
under a soft-drink can without the can toppling
because
A.
gravity pulls harder on the can than on the
paper.
B.
the can has weight.
C.
the can has inertia.
D.
none of the above

Newton's First Law of Motion
CHECK YOUR UNDERSTANDING
If you swing a stone overhead in a horizontal circle
and the string breaks, the tendency of the stone is
to follow a
A.
curved path.
B.
straight-line path.
C.
spiral path.
D.
vertical path.

Newton's First Law of Motion
CHECK YOUR ANSWER
If you swing a stone overhead in a horizontal circle
and the string breaks, the tendency of the stone is
to follow a
A.
curved path.
B.
straight-line path.
C.
spiral path.
D.
vertical path.

Newton's Second Law of Motion
•
The law of acceleration:
–
The acceleration produced
by a net force on an object is
directly proportional to the net
force, is in the same direction
as the net force, and is
inversely proportional to the
mass of the object.

Acceleration
net
force
mass
a
F
m
Newton's Second Law of Motion
•
Equation for acceleration:
Small net force, large
mass
small acceleration
Large
net force,
small mass
large
acceleration

Newton's Second Law of Motion
CHECK YOUR UNDERSTANDING
Consider a cart pushed along a track with a certain
force. If the force remains the same while the
mass of the cart decreases to half, the
acceleration of the cart will
A.
remain the same.
B.
halve.
C. double.
D.
change unpredictably.

Newton's Second Law of Motion
CHECK YOUR ANSWER
Consider a cart pushed along a track with a certain
force. If the force remains the same while the
mass of the cart decreases to half, the
acceleration of the cart will
A.
remain the same.
B.
halve.
C. double.
D.
change unpredictably.

Newton's Second Law of Motion
CHECK YOUR UNDERSTANDING
Push a cart along a track so that twice as much net force
acts on it. If the acceleration remains the same, what is a
reasonable explanation?
A.
The mass of the cart doubles when the force is
doubled.
B.
The cart experiences a force that it didn't before.

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- Spring '14
- AnnM.Robinson