forces core questions Flashcards
define speed
how much distance is covered in a given time
define acceleration
how much speed increases or decreases in a given time
state the equation for calculating speed
speed = distance/time
state the units for speed
m/s
what does a straight line on a distance-time graph show
object travelling at a steady speed
what does a curved line on a distance-time graph show
object speeding up or slowing down
what does a horizontal line on a distance-time graph show
object at rest not (not moving)
what is the unit for force
newton (n)
name the apparatus used to measure forces
newton meter
define force
a push or pull that acts on an object due to the interaction with another object
define contact force
a force that acts when objects are physically touching
define non-contact force
a force that acts when objects are physically separated
name five examples of contact forces
friction
air resistance
tension
compression
normal contact force
name three examples of non-contact force
gravitational force
electrostatic force
magnetic force
define resultant force
single force that can replace all the forces acting on an object and have the same effect
name two things that can happen when the forces on an object are balanced
object remains at rest
object remains at constant speed and direction
name four things that could happen when the forces on an object are unbalanced
object speeds up
object slows down
object changes shape
object changes direction
what would the resultant force on an object be if the forces are balanced
zero
what is the name of the diagram used to represent the forces acting on an object
free-body diagram
define friction
force opposing motion which is caused by the interaction of surfaces moving over each other
define drag
friction force when one object is a liquid or gas
define tension
force extending or pulling apart
define compression
force squashing or pushing together
define normal contact force
push force acting between two solid objects
define air resistance
friction force acting between an object and air particles
state two examples of situations where it is useful to reduce friction
sports
vehicles
state two ways of reducing friction or drag
make objects streamlined
use lubricants
state newtons third law
when objects interact the forces they exert on each other are equal and opposite
state the equation for hookes law
force = spring constant x extension
define moment of a force
the turning effect of a force
state the equation for moment of a force
moment of a force = force x distance to the pivot
state the unit for moment of a force
Nm (newton metre)
state what happens when the clockwise and the anticlockwise moments are equal acting on an object
the object balances
state the units of spring constant
newton per metre (N/m)
what happens when the clockwise and anticlockwise moments acting on an object are unequal
the object rotates
what is meant by the mass of an object
mass is a measure of how much matter there is in an object
what is the unit for mass
kg
what is meant by the weight of an object
weight is a measure of the size of the pull of gravity on the object
what is the unit for weight
newton (N)
what are the two factors that affect the pressure an object exerts
the force and the area over which the force is exerted
what is the equation for calculating pressure
pressure = force/area
