Forces in Physics

Study Notes

Forces Come in Pairs

A force is a push or pull resulting from an interaction between objects, and it is a vector quantity with both magnitude (how much) and direction (which way).
All objects can exert forces, even without touching, such as friction and gravity.
When there is an interaction, there will be at least one pair of forces in that interaction, even if the objects are not touching.

Forces Can Be Balanced

When the pair of forces are equal in size and opposite in direction, they are balanced, and the object will maintain its state of motion.
An object in mechanical equilibrium has no change in its state of motion, and the equation is ΣF = 0, meaning the vector sum of the forces is zero.
Mechanical equilibrium is not limited to objects at rest, but also includes objects traveling in a straight line path.
Examples of balanced forces include a person standing on the ground, a hanging basket, and a bowling ball rolling down a lane at a constant velocity.

Mechanical Equilibrium

Mechanical equilibrium is a state of no change in an object's state of motion.
It can be further divided into static equilibrium for stationary objects and dynamic equilibrium for moving objects.
Both types of equilibrium have balanced forces, resulting in no change in the object's state of motion.

Forces Can Be Unbalanced

Unbalanced forces are when the forces are not equal in magnitude, causing a change in the object's state of motion.
Unbalanced forces can start or stop motion, and are needed to get an object moving or to stop it from continuing along its path.
Examples of unbalanced forces include pushing a coffee table to get it moving, and a bowling ball hitting the pins and being disrupted from its path.

Description

Learn about forces, a push or pull resulting from interactions between objects, including magnitude, direction, and types like friction. Understand how forces can be exerted even without physical contact.