p9: forces Flashcards
(19 cards)
what is a scaler quantity
only has a size (magnitude)
what is a vector quantity
has both a size and a direction
what is a force
a push or pull that acts on an object due to the interaction with another object
is a force a vector or a scaler quantity
vector
what is a contact force
when objects are physically touching
e.g. tension , friction, air resistance
what is a non-contact force
when objects are physically separated
e.g. magnetic, electrostatic, gravitational
what is the same about the interaction pair of forces when 2 objects interact with each other
the forces are the same size
what is different about the interaction pair of forces when 2 objects interact with each other
forces are in opposite directions
what is the size of the resultant force on an object if the forces on it are balanced
zero
what is the name for the force acting on an object due to gravity
weight
what instrument can be used to measure the weight of an object
calibrated spring-balance
what is the centre of mass
the point through which the weight of an object can be considered to act
what is elastic deformation
an object can go back to its original shape and size when deforming forces are removed
what is inelastic deformation
and object does not go back to its original shape and size when deforming forces are removed
how do you find the spring constant from a force-extension graph of a spring
find the gradient of a straight line section
what is the turning effect of a force called
a moment
what can you say about clockwise and anticlockwise moments on a balanced object
sum of all the clockwise moments about any point = sum of all the anticlockwise moments about that point
how does a lever reduce the amount of force needed to create a particular sized moment
by increasing the distance form the pivot
what happens to the moment of a force when a small gear drives a large gear
moment is increased
