Projectile and Circular Motions
2D Motion
Two special types of motion in 2D
Projectile motion (today)
Uniform circular motion (tomorrow)
Key to remember that , , directions are independent of
each oth
Newtons First Law
Law of Inertia
Ancient Greeks:
The preferred state of all objects is to be at rest
=0
=0
Law of Inertia
Galileo:
In the absence of forces, the velocity stays the same
(This property
Sig. Figs. and Vectors
Significant Figures
True or False:
2 m = 2.00 m = 2.0000 m?
Math student says True
Science student (should) say False
Why the difference?
In science, we only write down digits c
Motion in 2D and 3D
Definitions
Position and Displacement
= + +
= 2 1 = 2 1 + 2 1 + 2 1
Definitions
Velocity
=
= lim
=
+
+
= + +
Were doing the same stuff as last week, but now in the
y and
Units
Why Units?
First, its required.
(This is physics, not math!)
Second, always asking how far/much/long need a way to
standardize measurements
All physical quantities have a unit, however a small
n
PHY 211 Homework #1
Due by 1am on Tuesday, September 6th
Submit your answers for the problems below on the course moodle page. By submitting this
assignment, you attest that youve done your own work.
PHY 211 Homework #3
Due by 1am on Tuesday, September 20th
Submit your answers for the problems below on the course moodle page. By submitting this
assignment, you attest that youve done your own work.
Physics 211
Physics for Science and Engineering I
Prof. Myers
My Story
Originally from Indiana
Physics and Math major at Indiana University
Ph.D. in Physics from the University of Illinois
Postdoctora
Kinematics I
Displacement
Velocity
Speed
Definitions and Relations
Position, Displacement, and Distance
Simplifications
1. Assume that we can describe all objects as point
particles (i.e. ignore si
PHY 211 Homework #2
Due by 1am on Tuesday, September 13th
Submit your answers for the problems below on the course moodle page. By submitting this
assignment, you attest that youve done your own work.
Newtons Second Law
Law of Inertia
The first law covers the case when = 0
What if the force is not zero?
=?
0
Observation
Acceleration increases if net force increases and/or
the mass decreases
Newton
Kinematics II
Motion with Constant Acceleration
The Big 5 Equations
Concept
Last time, we found velocity and acceleration from
position. But how can we find position from velocity
and/or acceleratio