Scribe Time

Hi this is benofschool, and I'll be your scribe for today...

We started off correcting chapter 11.2 Study Guide. So here are the answers:

enter, leave, external, conservation of energy, form, constant, created, destroyed, mechanical, decrease, simple harmonic, potential, kinetic, potential, kinetic, increases , decreases , friction , thermal

Here are the answers for the second paragraph:
shape, potential, kinetic, all, conserved, some, other forms, conserved

Now we corrected a couple of worksheets from the beginning of the week.
Here are the answers for Concept- Development Practice Page: Chapter 8: Energy

1)
W= Fd
W= 200N (4m)
W= 800J

2)
P = W/t
P = [200N(4m)]/4s
P = 200 watts

3)
P=W/t
P= 6000 watts or 6kw

4) 16nore (IGNORE :P)

5) 10 m/s of all of the cases. Apply trajectory formula to answer this question.

6) Block A wil reach the bottom of the incline first because of the incline's shorter distance.

7) 100J, 75J, 25J

8) 10 m/s for Points B, D, and E. Max Speed at Point C

9) Yes there will be a change in wind speed because the windmills will take some of the wind's kinetic energy.

That was it for that work sheet. There was one more. Diagram Skills Section 5-3.

1a) 0 J

b) E_p = mgh

c) E_k = (1/2)mv²

d) E = mgh_A - mgh_B

2a) 0 m/s

b)v= sqrt(2E_k/m)

3) First Column: All 0
Second Column: All 19110J
Third Column: 9555J, 12740J, 15925J, 3185J, 6370J
Fourth Column: 9555J, 6370J, 3185J, 15925J, 12740J
Fifth Column: 17m/s, 19.8m/s, 22.1m/s, 9.9m/s, 14m/s

4)The values are equal.

After that we took a look at our Work and Energy Booklet and learned about spring energy and the potential energy of the spring otherwise known as HOOKE'S LAW.

The formula for Hooke's Law is F = kx where F is the force, k is the spring constant, and x is displacement of the spring if it is stretched using the spring at normal length as the reference point. So now we can calculate the potential energy of the spring we are given a new formula derived from Hooke's Law and our good old area of a triangle of a Force vs Displacement graph.

W = area of a triangle
W = (1/2) F x
W = (1/2) k x x ---Now we substitute F for Hooke's Law
W = (1/2) kx²

Now we have 2 Potential energy formulae:

E_p = mgh
W = (1/2)kx²

We started working on a lab that involved Wind Up toys. This lab is due tomorrow I believe. Other than that just study up because the test on Circular Motion and Work and Energy will be on Wednesday November 12, 2008. The next scribe will be my best friend Rojuane...

Bye Bye