Answer the following with reference to the concept of force and Newton’s second law.
a. (i) Define force.
b. (ii) State the SI unit of force and express it in terms of the base units kilogram, metre and second.
c. (iii) State Newton’s second law of motion in words.
d. (iv) Write the vector equation that relates the net external force acting on a body of constant mass to its acceleration, clearly identifying each symbol.