Law of Universal Gravitation
Newton discovered that gravity is ...
universal
When is something weightless?
No support force or in free fall
What does the path of a projectile look like?
A curve
Why are satellites above Earth's atmosphere?
No air resistance
What do we call the oval path followed by a satellite?
Ellipse
What happens to gravity between objects as they get further away?
It weakens (inverse square of the distance between them)
When an elevator accelerates upward, your weight is...
Greater
What are two components of a projectile curve?
Horizontal and vertical motion
What is the shape of a satellite's orbit if it travels at a constant speed?
A circle
What is the speed of a satellite in an elliptical orbit like?
It varies
No matter how great the distance between two objects, the gravity approaches but never reaches...
zero
When an elevator accelerates downward, your weight is...
Less
Which projectile component is a constant motion?
Horizontal force
What is a projectile that continually falls around earth?
Satellite
When a projectile achieves escape speed from earth, what is it not beyond?
The influence of Earth's gravity
The force of gravity between two objects depends on what two things?
Mass and distance apart
What is your weight when you are in free fall?
zero
Which projectile motion accelerates?
Vertical force
When does a satellite with an elliptical orbit have its greatest speed?
When it is nearest to the Earth
How can a rocket be put into orbit?
Initially a vertical direction, then tipped horizontally
If the masses of two planets are each somehow doubled, the force of gravity between them does what?
quadruples
What is a force exerted against a supporting floor?
weight
What angle of a projectile would travel the same distance as a projectile released at a 60 degree angle?
30 degree angle
If you throw a ball horizontally, how far will the ball have fallen toward the ground after one second?
5 meters
What are the two types of orbits?
circular and elliptical