A car moves with constant speed 20ms−1 around a horizontal circular track of radius 50m. Consider the following physical quantities associated with this motion:
(A) linear speed, (B) linear velocity, (C) centripetal acceleration, (D) centripetal force, (E) angular speed, (F) time period.
a. (i) Classify each quantity (A–F) as a scalar or a vector, giving a brief reason in each case.
b. (ii) State, with justification, the direction of each vector quantity listed above at any instant of the motion. Use the terms “along the radius inward”, “along the radius outward”, “along the tangent”, or “directionless” as appropriate.
c. (iii) Explain why the term “centripetal force” does not refer to a new kind of force and identify two possible physical forces that can act as the centripetal force in different practical situations.