Join StudySoup

Get Full Access to
sc - PHYS 201 - Study Guide - Midterm

Description

Reviews

PHYS 201 – Dr. Wilson

Exam 1 Study Guide

Bold = Definitions Highlight = Formulas

Chapter 2 Motion in One Dimension

The Basics

∙ Position(x) vs time(t) graph

o Slope = speed

∙ Displacement the change in the distance traveled/position

displacement=∆ x=x−x0

∙ Speed the amount of distance you travel in a certain amount of time (the absolute value of the change in position over change in time) We also discuss several other topics like How does plasma membrane link adjacent cells together?

speed=|∆ x

∆t|

∙ Average Speed the total distance, s, traveled during a particular time divided by that time interval, t

average speed=total distance traveled

timeinterval for travel=st

∙ Constant uniform motion has a straightline connection between position (x) and time (t) – speed is constant

∙ Vectors have a size(magnitude) and direction

∙ Velocity is a vector, the quantity that describes both the direction and the speed of motion (the change in position over the change in time)

∙ Average Velocity the displacement divided by the time elapsed during that displacement (slope of straight line connecting the beginning and end of graph) final time−initial time=x2−x1

If you want to learn more check out How to calculate chained or chainweighted gdp?

velocity=⃗v=final position−initial position

t2−t1=∆ x ∆ t

∙ As we shrink our time interval, we start talking about instantaneous velocities o Instantaneous velocity the velocity at a particular point

∙ Acceleration change in motion

average acceleration=∆ v

∆t

∙ constant velocity = zero acceleration

∙ when things are increasing speed they have a positive acceleration, and when they are decreasing speed they have a negative acceleration We also discuss several other topics like Where does acetylcholine come from?

General Equations

a=constant

∙ x0 =initial position, v0 = initial velocity, a = acceleration, t = time v=v0+at

x=x0+v0t+12at2 Don't forget about the age old question of What are examples of elementary matrices?

∙ HINT: when solving equation problems, wait as long as possible before inserting the numbers (if you want to combine equations or solve for a specific variable)

Freefall

∙ Freefall the only force acting upon you is gravity (all objects fall at the same rate) ↓a=−9.8m/s2=−g

∙ a is no longer unknown

v=v0−¿ If you want to learn more check out How old is the universe according to big bang theory?

Don't forget about the age old question of Why is organismal diversity study important?

y=y0+v0t−12gt2

2(−g) ( y−y0)=v2−v02

∙ Freefall graph: (will always have a curve in the negative direction)

Chapter 3 Motion in Two Dimensions

The Basics

∙ Vector has magnitude and direction (can use an arrow to show a vector on a graph) ∙ Adding two vectors/Subtracting two vectors:

∙ Negative vector same length, opposite direction

∙ Components: a nice feature of vectors

⃗Cx,⃗Cy=components of ⃗C

length of ⃗Cx: cos30=Cx

C

length of ⃗Cy:sin 30=Cy

C

Rules of Trigonometry

SohCahToa

sinθ=opposite

hypotenuse

cos θ=adjacent

hypotenuse

tan θ=opposite

adjacent

∙ The sides of the above triangle are all connected with trig functions ∙ Pythagorean Theorem:

hypotenus e2=adjacent2+opposite2

hypotenuse=√adjacent2+opposite2

Kinematics (motion) in 2Dimmensions

average velocity∈the x−direction=v x=∆ x

∆t

average velocity∈the y−direction=vy=∆ y

∆t

average acceleration∈the x−direction=ax=∆ vx

∆t

average acceleration∈the y−direction=ay=∆ vy

∆ t

Constant Acceleration

∆ vx=v f−vi=v x−v x 0

∆ t=t−t0

ax=∆v x

∆t=vx−vx 0

∆t

∙ Projectile motion a=g=9.81m/s2

v x=v x0+axt

x=x0+vx 0t+12axt2

v y=vy 0+a yt

y=y0+v y0t +12ayt2

2 ay ( y−y0)=v y2−vy 0

2

What Causes Motion?

∙ Velocity is motion ( ⃗v ¿

∙ Newton’s 1st Law an object has a constant velocity unless a net force acts on it (forces cause changes in motion)

o ex: a book will remain at rest on a table because there is no net force acting upon it (gravity acts downward, but the table exerts an upward force of equal strength) ∙ Newton’s 2nd Law:

⃗Fnet=m a⃗

∙ Units: Newton! ( N=kg ms2)

∙ Forces can come from direct contact or action at a distance

o ex: when you drop a ball there is a net force (gravity) ⃗Fnet=⃗Fg=m ⃗ag=mg (downward)

∙ FreeBody Diagram a picture where we attach forces to an object (vectors)