interaction through the application of the forces (chapter 14)
type of forces
contact forces
non-contact force
there is contact force whenever an object touches something
examples for contact force: friction ( two force rubbing against on another)
a force that acts on an object without touching it
examples of non-contact forces:
electrostatic force : we can feel it when we use a transparent sheet of plastic to wrap a book
magnetic force: it is the force exerted nu a magnet on magnetic materials such as iron and steel
gravitational force: a force that attracts object to planet
measuring force
instruments for measuring
extension spring balance
compression spring balance
mass and weight
weight
mass
a measure of the amount of matter in a body
SI unit: kilogram (KG)
instrument used is:
beam balance
electronic balance
a measure of the gravitational force acting on an object
SI unit: newtons (N)
dependent on the location's gravitational field strength as give by this formula: weight = m x gfs
gravitational force IS NOT gravitational field strength
the mass of an object on earth will remain the same if on the moon
the weight of an object will change if on moon
instrument used: extension spring balance
speed
formula: speed = distant (m)/time (s)
effects of force
turning effects of forces
pressure
turning effects of forces is also known as moment or torque
when the perpendicular distance is the largest, the turning effect is the greatest
turning effect of forces is being applied when opening, using a crowbar and using a wheelbarrow
it is the amount of force acting perpendicular on a unit area
formula: force/area
to increase pressure, increase applied force and decrease contact area