Types of Forces
What is a force?
A push or pull on an object.
What is gravity?
The attractive force that exists between all objects that have mass.
What is friction?
The force that resists motion between two touching surfaces.
What is net force?
The combination of all the forces acting on an object.
What is zero?
When equal forces act on an object in opposite directions, the net force is this.
What are contact forces?
These forces act only when two objects touch.
What is the Law of Gravitation?
The law stating that all objects are attracted to each other by a gravitational force.
What is static friction?
This type of friction prevents surfaces from sliding past each other.
What is the sum of the forces?
If forces act in the same direction, the net force equals this.
What are balanced forces?
Forces that combine to form a net force of zero.
What are noncontact forces?
These forces act without touching (examples: gravity, magnetism).
What are mass and distance?
The gravitational force between two objects depends on these two things.
What is fluid friction?
This type of friction occurs between a surface and a fluid like air or water.
What is 10 N to the right?
If one force acts right (+20 N) and another left (–10 N), the net force is this.
What are unbalanced forces?
These forces cause a change in motion.
What is a Newton (N)?
The unit used to measure force.
What is weight?
The gravitational force exerted on an object.
What is microscopic roughness / friction?
Weak electrical attractions between atoms and molecules cause this effect.
Directions such as up/right/east being positive are known as this.
reference direction
What is inertia?
The tendency of an object to resist changes in its motion.
What is the length of the arrow representing in force?
On a force diagram, this feature of an arrow shows the strength of the force.
What is twice the weight?
If one object has twice the mass of another, it has this much weight.
What is a lubricant?
Oil or soap act as this to decrease friction.
What is add, using positive and negative signs?
When forces act in opposite directions, you still do this mathematical operation.
What is Newton’s First Law of Motion?
The law stating that if the net force on an object is zero, its motion does not change.