Classify the following amongst the contact and non-contact forces:
i) frictional force,
ii) normal reaction force
iii) force of tension in a string,
iv) gravitational force
Classify the following amongst contact and non-contact forces: (a) frictional force, (b) Normal reaction (c) force of tension in a string, (d) gravitational force, (e) electrostatic force, (f) magnetic force.