newtons 3rd law Flashcards
forces
what is a non contact force?
a force between objects when they aren’t touching
what is a contact force
a force between touching objects
what is a resultant force
the overall effect of a set of forces acting on a object
forces acting on an object can change its shape by…
stretching it, squashing it or twisting it
what is newton’s third law of motion
forces come in equal and opposite pairs which act on objects
a force acting on a object can change its motion by…
speeding it up, slowing it down, changing its direction or cause it to rotate
what’s the difference between a vector and scalar quantity
scalar quantities only have magnitude (size) whereas vectors have magnitude and direction.
how do we show vector quantities on diagrams
an arrow, starting at the point the force is acting pointed in the direction of the force.
what are forces measured in
forces are measured in newtons, N, but larger forces may be measured in kilonewtons, kN , or even meganewtons, MN.
examples of contact forces
friction, air resistances or normal reaction (an object rests on a surface)
examples of non contact forces
gravity, electrostatic force and magnetic force
what is newtons first law of motion
what happens to an object when there’s no resultant force acting on it
what is newtons second law
what happens to an object when there is a resultant force
pairs of forces are always…
the same size, act in opposite directions, act between just the two different objects and are the same type of force
