Classification of Forces
What is a force?
A push or pull on an object.
What does friction do to motion?
Slows it down\ resist motion
What is gravity?
A force that pulls objects toward each other.
What is the formula for calculating weight?
Weight = mass × gravity.
What is the normal force?
The force perpendicular to a surface that supports an object.
Name the two classifications of forces.
Contact forces and non-contact forces
Name a surface with high friction and one with low friction.
High: sandpaper; low: ice.
Which two factors affect the strength of gravitational force?
Mass and distance between objects
How is weight different from mass?
Weight depends on gravity; mass does not.
Where does the normal force act?
Upward, opposite to gravity, perpendicular to a surface
Give an example of a contact force
Friction, normal force, tension, etc
What type of friction occurs when an object rolls over a surface?
Kinetic Friction
What force keeps planets in orbit around the Sun?
Gravitational force
If gravity on Earth is 9.8 m/s², what is the weight of a 10 kg object? Show work
98 N.
Why does a book resting on a table not fall through it?
The normal force balances the book's weight
What classification of force acts at a distance without physical contact? Give an example.
Non-contact force, e.g., gravitational force.
Why do we need friction in everyday life?
It allows us to walk, drive, and hold objects.
Why do objects weigh less on the Moon than on Earth?
The Moon has less mass, so it exerts less gravitational force
What would happen to your weight if Earth's gravity doubled?
It would double.
True or False: The normal force is always equal to the weight of an object.
False, only when the surface is horizontal
Explain the difference between balanced and unbalanced forces.
Balanced forces cause no change in motion; unbalanced forces cause acceleration
What happens to friction if you increase the weight of an object?
Friction increases
True or False: Gravity acts only on objects with large masses. Explain
False, it acts on all objects with mass
On which planet would you weigh the most?
Jupiter, because it has the strongest gravity.
If a surface is tilted\ inclined, draw the normal force direction.
perpendicular to the surface