# F15 Mechanics Week 6

Day 1: Gravitational Energy and Escape Velocity
Integrate force to find potential energy for gravitational potential energy (graphs).
Use Conservation of energy in order to find velocity at different distances from a planet.

Before Class:
I posted very thorough solutions for PS #4 because it seems students are running into difficulty with vector components. Even if you are sure you’re doing great with this, please have a look at it. If you’re having difficulty, please spend some time with the solutions and make sure you can put the solutions away and then solve the problems on your own. I posted the solutions in both word and .pdf, so take your pick.

In Class

• Hand in PS#5
• Questions on PS#4, Please review solutions for PS#4

After Class

Day 2: Centripetal Acceleration and the Satellite Problem May update until class time Monday

Before Class

• Read Chapter 6 in your text. You don’t have to read it exhaustively, but please understand where the information is. Chapter 6.2 explains centripetal acceleration. 6.3 discussion forces that produce circular motion, using the word “centripetal force”, which I find to be a damaging term. Please come prepared to ask and answer the question, “why is there no such thing as ‘centripetal force’?” 6.4 deals with other fictitious forces like “centrifugal force” and “Coriolis Force”. It is important to know what these forces are… or claim to be so that you will know not to use them.

In Class

• Big Exam #4 – make sure you can derive the expression for centripetal acceleration

After Class

Day 3: Circular Dynamics

sum of the forces = m*a, for centripetal acceleration
Take away Concept: When dealing with circular motion, dynamics is just the same as always: the vector sum of the forces = m*a. The only difference is that “a” is centripetal acceleration.

Before Class:

In Class: Notice, MT2 is scheduled for Thursday of Week 7, next week.
Where do you weigh more on a perfectly spherical world: On the equator or at the pole?

Day 4: Trigonometry! Projectile Motion; Full Kinematics in one- and two-dimensions

In Class: Notice, MT2 is scheduled for Thursday of Week 7, next week.

• Use Algebra to solve one-dimensional problems – solve the “catching the bus”, or “catching the speeder” problem.
• Use trigonometry to solve projectile motion problems

Before Class

• From Textbook: Read chapter 2 – most of it is review, and you should skim over it. However, check out the stuff that’s new, and know where some of the other information.
• See and then you’re allowed to use those two unhelpful (in my opinion) equations, although hopefully, you’ve realized by now that you can get along without them just fine.
• See video on Pulling a Sled (added after F15)
• See video on Fuzzy Dice (added after F15)
• There is a centripetal acceleration video and one on the with Trig that could be altered and/or added here
• Read section 3.4 on projectile motion. See how they do it and compare it to the video on projectile motion.

In Class

• Shooting the Monkey
• problem solving! PS#6

After Class