Chapter 5 Forces Flashcards
“Dynamics” describes…
…how forces cause motion and changes in motion.
Definition of a force
a push or pull on a system; a force is a vector [has direction & magnitude (strength)].
Symbol F stands for…
magnitude (length or size/strength) of a force.
Definition of a newton
a unit of force
Difference between contact forces & field forces
Contact forces only act when systems/objects touch; field forces also act when systems don’t touch.
Definition of a field
a volume of space where every point has a different force value.
Principal field forces are…
…gravitational, magnetic, and electric
Newton’s 1st Law of Motion–Inertia–says…
…objects at rest remain at rest & objects in motion continue in a straight line at a constant velocity (speed/direction).
Newton’s 2nd Law of Motion–Accelerated Motion–is shown by the formula
F = m x a
Newton’s 3rd Law of Motion–Action/Reaction–says…
…for every force there’s an equal but opposite force.
Name 4 types of friction
static friction (between still objects); kinetic friction (between sliding objects); rolling friction, and fluid friction.
Newton’s Law of Universal Gravitation says:
the force of gravity between 2 objects is proportional to the product of their masses, so an object with twice the mass of another will have double the gravity.
Gravitational acceleration (g) at sea level on earth is…
…32 feet per second squared (aka 9.8m/s squared)
w = m x g means
weight of object (in newtons) = mass (kilograms) times gravity (the constant)
How to calculate the distance traveled by a moving object
distance = avrg rate of velocity x time traveled.
