Force is the thrust applied on a body to change its shape, size, state of rest or motion. It is measured in Newtons (N).
Mathematically, it is defines as  $$Force\left( f\right) =mass\left( m\right) \times accceleration\left( a\right) $$
Calculate the force applied on an object of mass 5kg moving with an acceleration of 9m/s.
f = m x a
$$Force\left( f\right) =5\times 9=45kgm/s^{2}=45N$$
Type of force  Name of the force  

Contact 


Noncontact 

Work is said to be done when a force moves an object by some distance.
Mathematically, work is force times distance.
$$W=F\times S$$
If F is the force acting on an object and moves it by a distance S, then work W is done.
Term  Unit  Symbol 

Force  Neuton  F 
Distance  meter  S 
Work  Joule  W 
A force of 0.5 neuton is applied on a box lying on a table and moved it by a distance of 1m. Find the work done in S.I. unit.
W = F x S
W = 0.5 x 1 = 0.5 Joule