Janna's Scribe for October 4th, 2010

Heyy everyone,

to start off class we watched a video that explored the concepts on impulse and momentum.

After watching the short video we went over the answers to the Chapter 9 Study Guide. The answers are as follows:

Section 9.1: IMPULSE and MOMENTUM

1. B

2. B

3. B

4. A

5. D

6. B

7. D

8. B

Next we went over the IMPULSE AND MOMENTUM sheet

1. WILL BE POSTED LATER

2.

a) m=Fg/g

=900N/9.8N/kg

=92kg

F∆t = m∆v/ ∆t

= (92kg)(2.0m/s)/ 0.70s

= 260N

b) p=m∆v

= (92kg)(2.0m/s)

=184N

260N - 184N =76N

3.

a) Ft =mv

=(51kg)(20.0m/s)

= 1020kg . m/s

b) F = mv/t seatbelt

= 1020kg.m/s/ 0.12s

= 8500N

F = mv/t noseatbelt
= 1020kg.m/s/ 0.008s
= 128000N

ALWAYS WEAR A SEATBLET WHEN IN A VEHICLE !!

Don't need to do #4

Next we watched three short clips regarding the momentum of a ball, recoil and the conservation of momemtum.

KEY CONCEPTS:

Remember momentum before a collision is equal to the momentum after a collision occurs.

For every action there is an equal and opposite reaction.

Homework:

Transparency 9-1 and 9-2 are due on Wednesday in class.

Have an awesome afternoon off !!! :)