A force is a push or pull that changes an object's shape or motion.
Measured in Newtons (N): 1N=1kg∗m/s2
Types of Forces
Contact Forces: Friction, normal, spring force (examples: pushing a box, book on a table, weight on a spring).
Non-Contact Forces: Magnetic, gravitational, electrostatic force (examples: interaction between magnets, trajectory of a ball, attraction between conductors).
Fundamental Forces
Gravitational Force: Attraction between objects with mass.
Electromagnetic Force: Holds together objects with opposite electrical charges.
Strong Force: Holds together objects with the same charge, like quarks within protons and neutrons.
Weak Force: Can change a quark from one type to another, leading to processes like beta decay.
Force as a Vector
Forces have magnitude and direction.
Represented by arrows; length indicates magnitude.
Balanced Forces
Equal in size and opposite in direction.
Net force is zero, no change in motion.
Unbalanced Forces
Cause a change in motion (acceleration).
Net force is greater than zero.
To find net force:
Same direction: add forces.
Opposite direction: subtract forces; net force is in the direction of the larger force.