Newton’s Laws Siml
Newton’s First Law:
Newton’s First Law: An Exploration
Open the Phet simulation entitled Forces and Motion: Basics
Newton's First Law states that "an object will remain at rest or in uniform motion in a straight line
unless acted upon by an external net force". It may be seen as a statement about inertia - that
objects will remain in their state of motion unless a force acts to change the motion.
Let’s see what this actually means using the simulation above.
1. Open the Simulation above and choose the Net Force window. Drag the people onto the
screen to create the situations below, hit the GO! button, then identify what part of
Newton’s First Law this agrees with. Select Sum of Forces, Values, and Speed so that we
can see all the data. Some cells are done to help you with the wording:
Situation: Net Force, Fnet What How does tis agree with
happens Newton’s First Law?
(= Sum of Forces)
?
No people 0N No motion Unless an outside force is
applied, objects at rest stay
at rest.
One medium person on 0N No motion The item remains at rest or
in motion because the
either side
external forces are equal.
Medium on Left, Large 50 N Right Object The item will move because
moves to the external forces are not
on Right
right equal.
, Two steps: 50 N Left Object Explain how the motion
moves to after the additional person
left is placed on the right
● Place two small people
agrees with the First Law:
on the left and one on
the right. The external forces acting
● Hit GO! on the item balance out,
keeping it traveling at the
same speed as before the
additional force was
applied.
● Watch the speedometer.
● While in motion add
another small person on
the right.
● Watch the speedometer!
2. Newton’s First Law is often referred to as the Law of Inertia. Inertia can be defined as the
“resistance of any physical object to any change in its velocity”.
a. Using the same simulation as above set up the following experiment below.
o Choose the Motion window (bottom of screen to select)
o Select Force, Values, Masses, Speed (upper right)
o Replace the 50kg box with the 40kg child
o Hit the pause button
o Use the “double arrows” to create a force of 100N
o Hit play and watch the Speedometer.
Newton’s First Law:
Newton’s First Law: An Exploration
Open the Phet simulation entitled Forces and Motion: Basics
Newton's First Law states that "an object will remain at rest or in uniform motion in a straight line
unless acted upon by an external net force". It may be seen as a statement about inertia - that
objects will remain in their state of motion unless a force acts to change the motion.
Let’s see what this actually means using the simulation above.
1. Open the Simulation above and choose the Net Force window. Drag the people onto the
screen to create the situations below, hit the GO! button, then identify what part of
Newton’s First Law this agrees with. Select Sum of Forces, Values, and Speed so that we
can see all the data. Some cells are done to help you with the wording:
Situation: Net Force, Fnet What How does tis agree with
happens Newton’s First Law?
(= Sum of Forces)
?
No people 0N No motion Unless an outside force is
applied, objects at rest stay
at rest.
One medium person on 0N No motion The item remains at rest or
in motion because the
either side
external forces are equal.
Medium on Left, Large 50 N Right Object The item will move because
moves to the external forces are not
on Right
right equal.
, Two steps: 50 N Left Object Explain how the motion
moves to after the additional person
left is placed on the right
● Place two small people
agrees with the First Law:
on the left and one on
the right. The external forces acting
● Hit GO! on the item balance out,
keeping it traveling at the
same speed as before the
additional force was
applied.
● Watch the speedometer.
● While in motion add
another small person on
the right.
● Watch the speedometer!
2. Newton’s First Law is often referred to as the Law of Inertia. Inertia can be defined as the
“resistance of any physical object to any change in its velocity”.
a. Using the same simulation as above set up the following experiment below.
o Choose the Motion window (bottom of screen to select)
o Select Force, Values, Masses, Speed (upper right)
o Replace the 50kg box with the 40kg child
o Hit the pause button
o Use the “double arrows” to create a force of 100N
o Hit play and watch the Speedometer.
