Review Session “What we done?” Baron von Frankenstein

For Wednesday’s Exam Pencil Calculator (Cheap is fine) Be ON TIME Know your PID and bring ID card with you.

CHAPTER 1.5 NOTE DOCUMENT ON SITE THAT CONTAINS THE MUSIC RELATED MATERIAL THAT WE HAVE COVERED TO DATE IT ALSO CONTAINS MATERIAL THAT WE HAVE NOT COVERED Background Material

Question Is anyone having problems downloading lecture set 5? Send an with PC and OS information.

Basic Topics Background Material on Scientific Method ◦ Mostly reading ◦ Bode’s Law  Not important but is an example of someone whose results were invalidated by later observations.  This concept of testing and retesting a “Law” or Theory and modifying to include both new and older information is the foundation of modern physical science

WHAT ARE SOME EXAMPLES OF LAWS/THEORIES THAT ARE CURRENTLY ACCEPTED AS GOOD MODELS

How about Murphy’s Law?? If it can go wrong, it will. The toast will always fall buttered side down.

Can you do “scientific notation”? Etc.

WHAT DID HE DO? WHY WAS IT IMPORTANT? Boltzman

Remember this (see site)? ope n close d T=~2ms=0.002 seconds

Period = T=~2ms=0.002 seconds

Don’t forget Milli = 1/1000 Millimeter = 1/1000 meter = meter Milli-second = 1/1000 sec = seconds 1 Kg = ? 1 M Hz =

Standards Why do we need them What are they ◦ Time ◦ Distance ◦ Mass

Dynamics Concept of equilibrium Velocity ◦ Change in “distance” /time Acceleration ◦ Change in velocity (speed?)/time Concept of average speed and velocity Concept of average acceleration The nature of VECTORS

A runner leaves home for a training session. He typically runs at a speed of 8 miles per hour. It takes him two hours to make the trip. ◦ What was his average speed? ◦ What was his average velocity? ◦ What was his average acceleration? ◦ How far did he run? ◦ What color underwear was he wearing?

Acceleration of Gravity What is g? I throw an object up with a speed of 30 m/s, ◦ how long does it take to get to the point where it stops? ◦ How much longer does it take to be falling at a speed of 15 m/s Do it a step at a time.

A woman throws a 50kg vertically with an initial speed of 20 m/s. How far does it travel to the point where it is at rest? The initial velocity is v 0 20 m/s The final velocity is zero The acceleration is –g ◦ (MINUS.. Against the original throw.) It travels for 2 seconds Let’s look at the graph

Graph (m/s vs. sec) – Example uniform acceleration: v=at time velocity v v+  v Area=v  t =  x Area=(1/2 base x height) Area = distance traveled Area=(1/2)vt=(1/2)at x t Area=dist=(1/2)af 2

You plan to drive 60 miles with the cruise control set at 50 mph. How long will it take to get there?

Newton’s Laws Newton 1 ◦ A body at rest or moving at a constant velocity will tend to remain at rest or at the same constant velocity unless acted upon by an external force. Newton II ◦ A body subjected to an unbalanced force (F) will accelerate (a) at a rate that is proportional to the unbalanced force. ◦ The relationship DEFINES the concept of mass or inertia

Newton’s Laws

Frank is holding 10 pounds of groceries. He weighs 300 pounds. How large is the normal force? ?

Question When the same net force is applied to object A and object B, object A has an acceleration three times that of object B. Which of the following is correct? a. Object A has three times the mass of object B. b. Object A has one ‑ third the mass of object B. c. Object A has a different, less streamlined shape than object B. d. Object A has more friction than object B.

A ball with a weight of 20 N is thrown vertically upward. What are the size and direction of the force on the ball just as it reaches the top of its path? a. zero b. 10 N upward c. 10 N downward d. 20 N downward

A ball falling from a great height will reach terminal speed when its _____ goes to zero. a. inertia b. net force c. weight d. speed

A crate has a mass of 24 kg. What applied force is required to produce an acceleration of 3 m/s 2 if the frictional force is known to be 90 N? a. 72 N b. 90 N c. 162 N d. 240 N

A ball with a weight of 20 N is thrown vertically upward. What is the acceleration of the ball just as it reaches the top of its path? a. zero b. 10 m/s 2 downward c. 10 m/s 2 upward d. The acceleration cannot be determined. A ball with a weight of 20 N is thrown vertically upward. What is the acceleration of the ball just as it reaches the top of its path? a. zero b. 10 m/s 2 downward c. 10 m/s 2 upward d. The acceleration cannot be determined.

A ball with a weight of 20 N is thrown vertically upward. What are the size and direction of the force on the ball just as it reaches the top of its path? a. zero b. 10 N upward c. 10 N downward d. 20 N downward A ball with a weight of 20 N is thrown vertically upward. What are the size and direction of the force on the ball just as it reaches the top of its path? a. zero b. 10 N upward c. 10 N downward d. 20 N downward