(1) resultant forces Flashcards
what can forces change
- the shape of an object
-its state of rest
-its motion
give 3 examples of noncontact forces
-gravity
-electrostatic energy
-magnetism
give 3 examples of contact forces
-friction
-air resistance
-tension
whats the unit of force
Newtons
what happens when 2 objects interact
they excert an equal and opposite force on eachother
whats friction
a force that opposes the motion of any 2 surfaces in contact with eachother when they try to slide past eachother
whats a resultant force
a single force that has the same effect as all the forces acting on an obhect
what does newtons1st law of motion state about zero resultant force
if the resultant force on an object is 0, the object
-remains at stationary if it was at rest
or
-continues to move at the same speed and direction as it was
if a resultant force is 0 and only 2 forces are acting on the object then..
those 2 forces must be equal and act in opposite direction to eachother
what can we conclude when the resultant force is not 0
the forces acting on the object arent balanced
hoe do vectors show the force of an object in diagrams
each force is reprsented by a vector which is shown as an arrow
-the length of the arrow is proportional to the size(magnitude) and point to the direction
if an object is acted on by 2 unequal forces then the resultant force is..
-equal to the difference between the 2 forces
-in the direction of the larger force
what does the parallelogram of forces show us
the resultant forces of 2 forces that dont act on the same line
what are scalars
quantities that have ONLY a magnitude(size)
whatre vector quantities and how are they represented
vectors have both direction and magnitude(size)
theyre represented by arrows. the length of an arrow shows the magntiude and the direction its pointing at shows us direction
define weight
the force of gravity on an object due the gravitational attraction between the object and the earth
whats the unit for weight and mass
weight- Newtons
mass- Kg
whats the formula that relates weight,mass and gravitaty
w=mg
where w is weight in newtons
m is mass in kg
and g is gravitational field strength in N/Kg
when can we call an object elastic
if it returns to its original shape after you remove the force deforming it
whats an extention and how can you calculate it
an increase in length of a stretched material from its original length, its calculated each time a weight is added
extention=stretched length-original length
whats the relationship between spring extentions and the force applied to it
theyre directly proportional, as long as limit of proportionallity(stretched beyond its limit) isnt exceeded
whats the equation for hookes law
force=spring constant X extension
what happens when an elastic object is stretched
elastic potential energy is stored in the object because work is done on the object by the stretching force
