Force Pairs
What is the reaction force that always acts perpendicular to an object's surface?
normal force
Two cars colliding head on and sticking together are an example of what kind of collision?
inelastic collision
Gravity is a _____________ force that one object can apply to another object without touching it.
non-contact
What has more gravity than anything else in the solar system?
The Sun
On Earth, what is the acceleration of a falling object due to gravity?
9.8 m/s2
Which of Newton's laws of motion is most closely associated with force pairs?
Newton's 3rd Law
In what type of collision do objects collide and bounce off of each other?
Elastic Collision
In order for any object to exert gravity, it must have what?
mass
What has more gravity than anything else in the universe?
black hole
Throwing a dart at a dartboard is an example of what type of collision?
Inelastic collision
If two forces result in a net force of zero, what kind of forces are they?
balanced forces
What are three unique examples of an inelastic collision?
Any three examples where two objects collide and stick together
How does gravity exert force?
Through a gravitational field
What does the Moon affect on Earth through its gravitational field?
High tides and low tides of the Earth's oceans
On Earth, an object has a weight of 980 Newtons. What would its mass be?
100 kg
When any object applies force on a second object, how would you describe the force of the second object?
The second object applies a force of the same strength on the first object, but the force is in the opposite direction.
In the real world, there is no such thing as a 100% perfectly elastic collision. Why is this?
Some kinetic energy is always lost due to the sound made by two colliding objects.
Why are objects on Earth's surface not attracted to each other through gravity?
Because the Earth itself has so much more mass than any objects on the Earth's surface.
How does gravity affect objects that are dropped in a vacuum?
When the only force acting on a falling object is gravity, all objects fall with the same acceleration.
Why are mass and weight not the same?
Mass is a measure of the amount of matter in an object. Weight is a measure of mass times the acceleration due to gravity. Weight can change depending on where in space an object is, but as long as an object is constant, its mass will always remain the same regardless of where it is in space.
Explain the difference between force pairs and balanced forces.
A force pair is the forces two objects apply to each other. Force pairs are not the same as balanced forces. Balanced forces act on the same object. In force pairs, each force acts on a different object.
Explain what happens to momentum and kinetic energy in both types of collisions.
In an elastic collision, momentum and kinetic energy are both conserved. In an inelastic collision, momentum is conserved, but some kinetic energy is lost as heat, sound, or shape change.
Explain the relationship between distance and gravity and mass and gravity.
When the mass of one or both objects increases, the gravitational force between them also increases. This is a direct proportional relationship. As the distance between objects increases, the gravitational force between them decreases. This is an inverse proportional relationship.
Explain the interaction between air resistance and gravity.
Objects with little mass and density such as feathers or paper are opposed by the force of air resistance. Air resistance opposes gravity as an object falls.
If you wanted to decrease the gravity on the Earth, explain the two ways you could do this.
You could decrease the mass of the Earth and/or Sun or you could increase the distance between the Earth and the Sun.