hw from class today

Remember to revisit the igloo problem, seeking the alternate solution. 2/3 is indeed the answer.

Also, catch up on reading in the two energy chapters (7 and 8), focusing on the relationship between force and potential energy (derivative), discussed in 8-6.

Try also the Tarzan problem (8-25).

energy problems

1. Consider a brick dropped from a 15-m height. Find the following:

a. initial potential energy
b. kinetic energy immediately before hitting the ground
c. velocity immediately before impact with ground
d. velocity at a point half-way down

2. Consider a "loop the loop," in which a small mass is dropped from some height (H) and is free to slide frictionlessly until reaching a loop of radius r. (See picture on page 190, problem 8, for clarification).

What is the minimum height (H) so that the mass will "just make" the loop? Solve in terms of r (loop radius). [answer: H = 5r/2 (or 2.5r)

3. A large mass (m --> see, I told you it was large!) is moving at a speed v. It hits a friction-y surface (u) and slides to a halt. What is the distance that it will travel before completely stopping? (Solve for the distance in terms of relevant variables.)

Text problems worth a look, in this order (in case you are limited for time):

Chapter 8:

9 (watch units)
21
15
36* (tricky, but fun!)

Looking ahead

Flight data, take 1

HW

Hiya. Fun launching today, despite the ridiculous problems.

Try these problems, if you have time. Pick and choose, if time is short for you.

Chapter 6: 41, 43, 53, 81
Chapter 9: 29

Thank you.

Hw

Please read in chapter 9 - sections 3-7, 12

The momentum concept is an extension of Newton. If energy means nothing to you yet, don't worry about it.

Again, apologies for delay.

homework

Folks,

I've had a crisis to deal with so I was not able to post homework in a timely fashion. Also, I left my text at school. I'll post a couple of problems tomorrow morning. If you have time to try them, great. If not, I won't hold it against you.