1. PHYSICS DAY 35 Here we go! Today: 1) 2 forms of energy
2) Examples, using tables, math
3) Work as an idea
4) Energy bar graphs

2. Go to the handout. Lets fill in some basic things:

3. Work/Energy Review…a set of ideas
Remind Me:
Kinetic Energy
Idea: Equation:
Grav. Potential Energy

4. The change of an energy type is called:
In an isolated system, how should the total amount of energy compare before and after some time?

5. Kinetic Energy
(1/2)m(v2)
Gravitational Potential
m(g)h
System Energy
At starting height
Striking the floor

7. Lets Try Some
In this coaster

8. Kinetic Energy
(1/2)m(v2)
Gravitational Potential
m(g)h
System Energy
At A
At B
At C

9. THE SAME! No loss of system energy!
Lets Try Some
If this is an isolated system, how does the system energy at A compare to C?
THE SAME! No loss of system energy!

10. A has MORE GPE because it is higher!
Lets Try Some
If this is an isolated system, how does the Potential energy due to gravity at A compare to C?
A has MORE GPE because it is higher!

11. Lets Try Some
Now lets come up with a sentence to describe what is happening to the system energy between:
A and B also B and C

12. Would a heavier cart have more/less/same speed at C?
Lets Try Some
Would a heavier cart have more/less/same speed at C?

13. Lets See and Draw a Roller Coaster
This is the TOP THRILL DRAGSTER.
Height of the coaster: 420 feet tall (130m)
Accelerated to a speed of 120 mph (190 km/h) in 3.8 seconds and then begins to vertically climb.
17 seconds for the ride
18 riders per train, train mass is 15 tons (13,600kg) empty.
Lets see it!

14. 5 dots correspond to different parts of the ride.

15. So Lets DO A Bar Graph
Lets compare the bottom and top

16. So Lets DO A Bar Graph
Lets compare the bottom and halfway up.

17. BUT WHAT IF IT WAS NOT ISOLATED?
What would happen?

18. So Lets DO A Bar Graph
Lets compare the bottom and top.

19. Lets do Some HW to understand

20. First thing in your detector: SLOW CONSTANT SPEED and MECHANICAL of EARTH-BOOK.
Does this system include the PERSON?
So should this SYSETM be isolated?