When the velocity of an object decreases with time, it is called retardation or de-acceleration or negative acceleration.

Only magnitude is required to specify the speed of an object as it is a scalar quantity.

Any substance that contains only one type of particles (example, molecules or atoms etc) is said to be a pure substance. Among the given options only distilled water has one type of particles (that is H₂O molecules).

Class 9th Science Session 2022-23 Class 9 Science Terminal Exams MCQ Solutions 9th Science Terminal Exam Based MCQ Extra Questions Class IX Science MCQ Extra Questions Answers

False, Displacement is the length of shortest path between initial and final position. So, its magnitude can never be greater than the distance travelled by it.