forces and newtons law Flashcards
Frictional force
The force that opposes the motion of an object
(acts parallel to the surface with which the object is in contact)
Normal force
The perpendicular force exerted by a surface on an object in contact with it
Gravitational force
the gravitational force the earth exerts on any object on or near its surface
Resultant vector
the single vector which has the same effect as the original vectors acting together
resultant force
sum of all forces on an object
why will different sized objects fall and hit the ground at the same time
due to gravitational acceleration
the heavier object has more mess and hence a larger inertia
therefore the earth exerts a larger force on it to accelerate it at the same rate as the lighter object
why will a heavier object experience a greater force
object will have a greater resistance to change (mass is an indicator of inertia)
inertia
the property of an object that causes it to resist a change in its state of rest or uniform motion
how does normal force acts
acts upwards perpendicular to the surface
balances out Fg
how do you reduce friction
lubricants
what is unhelpful friction
moving parts in a car generating heat
boat on water - water slows the boat down
helpful friction
air resistance creates drag on a parachute
car tyres on a road- stops sliding and helps the car to be able to slow down
Newtons third law of motion
When object A exerts a force on object B, object B simultaneously exerts an oppositely directed force of equal magnitude on object A
what is N3 about
interaction between pairs of objects
action reaction/N3 pairs
same type of force
same magnitude
occur simultaneously
act along the same line
opposite direction (act on different objects- therefore cannot balance each other out)