{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lect02

# Lect02 - Physics 112 Lecture 2 Agenda for Today 1-D...

This preview shows pages 1–10. Sign up to view the full content.

Physics 112: Lecture 2 Agenda for Today 1-D Kinematics 1-D Kinematics – Average & instantaneous velocity and acceleration – Motion with constant acceleration

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Motion in 1 dimension In 1-D, we usually write position as x(t). Since it’s in 1-D, all we need to indicate direction is + or . Displacement in a time Δ t = t 2 - t 1 is Δ x = x(t 2 ) - x(t 1 ) = x 2 - x 1 t x t 1 t 2 Δ x Δ t x 1 x 2 some particle’s trajectory in 1-D
1-D kinematics t x t t ) t ( x ) t ( x v 1 2 1 2 av Δ Δ = t x t 1 t 2 Δ x x 1 x 2 trajectory • Velocity v is the “rate of change of position” Average velocity v av in the time Δ t = t 2 - t 1 is: Δ t V av = slope of line connecting x 1 and x 2 .

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Consider limit t 1 t 2 Instantaneous velocity v is defined as: 1-D kinematics... dt ) t ( dx ) t ( v = t x t 1 t 2 Δ x x 1 x 2 Δ t so v(t 2 ) = slope of line tangent to path at t 2 .
Puzzle Yesterday I was driving down Green Street, when I was stopped by a police officer. He said to me “You were going 60 miles an hour.” I responded, “I’ve only been driving for 10 minutes! How could I possibly have gone 60 miles an hour, when I haven’t even been traveling for an hour?” What’s wrong with my argument?

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Graph of x(t) versus time, what’s the average velocity? T
Definition of SPEED: distance traveled without regard to direction, divided by time t. What’s the average speed? Average speed average velocity!

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
1-D kinematics... t v t t ) t ( v ) t ( v a 1 2 1 2 av Δ Δ = • Acceleration a is the “rate of change of velocity” Average acceleration a av in the time Δ t = t 2 - t 1 is: And instantaneous acceleration a is defined as: 2 2 dt ) t ( x d dt ) t ( dv ) t ( a = = dt ) t ( dx ) t ( v = using
Recap If the position x

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern