Question

name:
pd: 2 date: 01/21/26
8-5: free fall and circular motion
apple falling from the tree
stone dropped down from a hill
understanding main ideas
1 free fall is when the only force acting on an object is (______).
gravity
2 what is the acceleration due to gravity?
the constant rate
3 a squirrel drops a nut over a cliff. ignoring air resistance, what is the velocity of the nut after:
a. 3 seconds?
b. 5 seconds?
4 objects that orbit around other objects in space are called ().
5 satellites in orbit around earth continually fall toward (______).
6 once it has entered a stable orbit, a satellite continues to move ahead due to its (______).
7 most satellites are launched at a speed of about (____).
8 a force that causes an object to move in a circular path is called (_) (_).
9 an object traveling in a circle is accelerating because it constantly (_)(____).
10
centripetal means “(_) (_)”
11 if you could turn off the centripetal force, the object would fly off in a (_) (___).

Explanation:

1. Defines the key force in free fall.
2. States the standard gravitational acceleration value near Earth's surface.
3. Uses the free fall velocity formula $v = gt$ where $g=9.8\ \text{m/s}^2$.
4. Identifies the term for orbiting space objects.
5. Notes the direction of gravitational pull for Earth satellites.
6. Identifies the property keeping satellites moving forward.
7. States the typical orbital launch speed for Earth satellites.
8. Names the force for circular motion.
9. Explains why circular motion involves acceleration.
10. Gives the literal meaning of "centripetal".
11. Describes the path of an object when centripetal force is removed.

Answer:

1. gravity
2. $9.8\ \text{m/s}^2$ (or 32 ft/s²)
3. a. $29.4\ \text{m/s}$

b. $49\ \text{m/s}$

1. satellites
2. Earth
3. inertia
4. 8 km/s (or 18,000 mph)
5. centripetal force
6. changes direction
7. center seeking
8. straight line