Position, Velocity, and Acceleration

Announcements

Understand all material in assigned chapters whether in lecture or not. Read Ch 1-2 for next week.

HW 1 is due 1 AM this morning.

Help sessions begin next week – across from 113

One 3x5 index card is allowed for any quiz or test.

Expect unit conversion and scientific notation problems. NO CALCULATORS allowed on first quiz.

HW 2 has some units and sci. notation problems on it.

HW Software

The science that studies matter, energy, force, space, time, and the interactions between them.

Basic Formulae – Clicker Q #1Physicists simplify the universe into planes, cubes,

circles, lines, cylinders, and particularly – spheres! You are assumed to know the length, area and volume formulae from geometry

A sphere has radius R, it's surface area and A sphere has radius R, it's surface area and volume are, respectively:volume are, respectively:

A) R2 & 4 R

B) 2 R & 4 R2

C) 4 R2 & 8 R3

D) 4 R2 & (4/3) R3

E) (4/3) R3 & 4 R4

Average vs. instantaneous velocity

How do you get the slope of a curve?

Getting velocity from position vs. time graphs

Getting acceleration from velocity vs. time graphs

Relation between position, velocity, and acceleration

Obtaining v and a from graphs(clicker #2 and #3)

v from x vs. t (clicker #4)

a from v vs. t (clicker #5)

x vs. t – not y vs. x

INSTS = vr

Instantaneous Speed

Instantaneous speed is

Magnitude of instantaneous velocity

AV

∆∆x

v =t

Average Velocity

Total displacement (delta-x) in delta-t divided by delta-t

Instantaneous Velocity

Instantaneous velocity (or just “velocity”) is displacement dx in infinitesimal time dt divided by dt.

d

d

xv =

t

0 0lim lim AVt t∆� ∆�

∆ =∆x

v = vt

Displacement

Position

∆x

x Coordinate of object at time t.Difference in coordinate between time t and later time ∆t + t

1-Dimensional motion definitions

Position, velocity, and acceleration

Velocity dxv =

dt

Position x

Acceleration dva =

dt2

2

d xa =

dt

m

ms

2ms

Equations for the week