Question

Which of the following can be used to describe how fast an object is moving along with the direction of motion at a given instant of time?

(a) Instantaneous velocity

(b) Instantaneous speed

(c) Average velocity

(d) Average speed

This question was posed to me in a national level competition.

This interesting question is from Straight Line Motion topic in chapter Motion in a Straight Line of Physics – Class 11

Answer 1

Correct answer is (a) Instantaneous velocity

The best I can explain: Instantaneous velocity describes the velocity of an object at a given time instant. Average speed is the speed at which the object travels throughout the time period and not an instant. Speed is a scalar quantity; hence it cannot show the direction of motion.