Chapter 4

Section 2

Checking Up:

1. It doesn't affect it, changing the height of where it is dropped from is what changes the speed
2. The GPE decreases because the height above the ground level is decreasing.
3. The KE and GPE have to be equal
4. It turns into KE
5. 3/4 of 40,000= 13,333

Section 4

What do you see?

• the roller coaster on the moon is not as fun as the one on Jupiter

What do you think?

• Gravity pulls you toward the center of the object
• Gravity is pulling them to the center of the earth so they are not upside down

Checking Up

1. The middle of the room
2. It is stronger when the lines are closer together
3. It becomes 1/3^2 or 1/9
4. celestial force
5. ellipses

Investigate

On worksheet

Section 6

Physics to Go

1.
a. 19.6
b. 49
c. 98
2.
a. 3.2
b. 8
c. 16
3.
a. No
b. Yes
c. No
4.

	Acceleration	Scale Reading
Elevator at rest on top floor	zero	equal
Elevator starts moving down	down	smaller
Elevator moves down at constant speed	zero	equal
Elevator comes to rest on bottom floor	up	larger
Elevator is at rest on bottom floor	zero	equal
Elevator begins to move up	up	larger
Elevator moves up at constant speed	zero	equal
Elevator comes to rest on top floor	down	smaller
Elevator at rest on top floor	zero	equal

5. The elevator is going down
6. It will go down
7.
a. decrease
b. 415
8.
a. 490N
b. 590N
c. 490
9. The elevators have different accelerations

Section 7

Physics to Go
1.
a. on paper
b. on paper
2.
a. centripetal force
b. on paper
3. The acceleration becomes greater making ti harder for her to hold onto the key chain
7. Ac= 20^2/200= 2m/s
8.Bottom-Fn, Fg, Fc &Top Fn, Fg,Fc
9. Fc= Fn+Fg
10.

Fast Moving Roller Coaster
	Required Centripetal Force	Force of Gravity	Normal Force
Top of Loop	4,000N	500N	3,500
Bottom of Loop	6,000N

Slow-Moving Roller Coaster
	Required Centripetal Force	Force of Gravity	Normal Force
Top of Loop	800N
Bottom of Loop	2,800N