Forces and their interactions

magnitude

size/distance

displacement

distance moved in a straight line in a given direction

vector

direction+ magnitude

scalar

magnitude

power

rate at which work is done/ energy transferred

force

push or pull on an object (vector quantity)

contact force

when 2 objects are physically in contact with each other

non-contact force

when the objects are not touching

weight

force that acts in mass due to gravity

gravity

force that attracts an object towards the centre of the earth

resultant force

overall force acting on an object taking into account all the forces acting on it

equilibrium

when all the forces acting on an object balance out

work done

energy transferred

forces

push or pull that acts on an object due to the interaction with another object

Name as many forces as I can + state if it is contact or non-contact

Friction-contact

gravity- non-contact

upthrust- contact

magnetic- non-contact

weight- non-contact

normal contact force- contact

tension- contact

electrostatic- non-contact

compression- contact

drag- contact

the strong force- non-contact

how to name forces (3marks)

• type of force

• what the force is acting on

• what it is interacting with

• e.g force of gravity on the ball from the earth

name vector quantities

• force

• acceleration

• velocity

• displacement

name scalar quantities

• length

• pressure

• mass

• resistance

work done equation

work done(J) = force(N) x distance (m)

elastic deformation

the object will return to its original shape when the deforming force is removed

inelastic deformation

the object will not return to its original shape when the deforming force is removed

Hooke’s law (law of elasticity)

the extension of a spring is directly proportional to the force applied to it, provided the law of proportionality is not exceeded

extension

length of the material when its force is applied

extension equation

f= kx

force applied on the spring= spring constant x extension of the spring

what is spring constant

measure of stiffness of the spring

What is the required practical for force and extension

investigate the relationship between the weight hung from the spring and the extension

how to find spring constant (from a graph)

1/ gradient

elastic potential energy

the energy stored as a result of deformation of an elastic object, for example the stretching of a spring

elastic potential energy equation

Ee= ½ ke²

elastic potential energy(J) = ½ spring constant (n/m) extension² (m)