LP Physical Science: U7 Momentum

Lesson Plan for Physical Science Unit 7 – momentum. Link to math-science-resources PIXAR video – “A Tale of Momentum”.

 

 

Textbook(Hewitt – Physical Science) Ch 3.

Standards – from CAL CST
Conservation of Energy and Momentum

2. The laws of conservation of energy and momentum provide a way to predict and describe the movement of objects. As a basis for understanding this concept:

a. Students know how to calculate kinetic energy by using the formula E=(1/2)mv2 .
b. Students know how to calculate changes in gravitational potential energy near Earth by using the formula (change in potential energy) =mgh (h is the change in the elevation).
c. Students know how to solve problems involving conservation of energy in simple systems, such as falling objects.
d. Students know how to calculate momentum as the product mv.
e. Students know momentum is a separately conserved quantity different from energy.
f. Students know an unbalanced force on an object produces a change in its momentum.
g. Students know how to solve problems involving elastic and inelastic collisions in one dimension by using the principles of conservation of momentum and energy.
h. * Students know how to solve problems involving conservation of energy in simple systems with various sources of potential energy, such as capacitors and springs.

LESSON PLAN ————————————
APK: pushing objects hard * short period of time == softly * long period of time
introduce the idea of Impulse as force x time.
quick verbal questions like 1,000N x 1 sec == same impulse as 1 N x 1,000 sec.

STATE: The Impulse causes a change in motion, but the mass of the object stays the same.

Defn: momentum p = mv
Show video; link http://math-science-resources.com/physics-unit-5-impulse-and-momentum/
play it through1 time, play frame by frame, class describes exactly what’s happening at each point ie v is increasing, stone breaks etc. energy is being dissipated due to friction when the monster tries to slow the rock to save the kingdom of Frymburk.
sample eqns:
use still frame in post beneath video
say rock has a mass of 10,000kg (q: how much does it weigh)
assume half way down the rock is moving at 10 m/s
calculate p
then the rock breaks into 2 separate halves – are they going at the same speed?
calculate p for each half
p = mv = 5,000kg x 10 m/s = 50,000 kgm/s
p1 + p2 = 50,000 kgm/s + 50,000 kgm/s = 100,000 kgm/s or 100,000 N-s

Derive units of N-s
Σp initial = Σp final

Conservation of Momentum Theorem

Reading Assignment: Sections 3.1 & 3.2 pg 59 – 62.

P.Sci ppts are on the resource link (inlyif there’s time): http://math-science-resources.com/category/physical-science-unit-7-momentum/