Question:
Given below are two statements:
Statement I: The mass of an object is a measure of its inertia.
Statement II: Force of friction always opposes motion of objects.
In the light of the above statements, choose the most appropriate answer from the options given below:
(A) Both Statement I and Statement II are correct
(B) Both Statement I and Statement II are incorrect
(C) Statement I is correct and Statement II is incorrect
(D) Statement I is incorrect and Statement II is correct
Answer : (C) Statement I is correct and Statement II is incorrect
Analysis of the Statements
Here’s a breakdown of the two statements from physics:
- Statement I: The mass of an object is a measure of its inertia.
- This is correct 👍. This is the fundamental definition of inertial mass. Inertia is an object’s inherent resistance to any change in its state of motion. Mass is the physical quantity that measures this inertia. For example, a large boulder (high mass) has more inertia than a small pebble (low mass), making it much harder to start moving or to stop once it’s in motion.
- Statement II: Force of friction always opposes motion of objects.
- This is incorrect ❌. This is a common oversimplification. The force of friction opposes the relative motion or tendency of relative motion between surfaces in contact. It does not always oppose the overall motion of an object.
- Example – Walking: When you walk, you push your foot backward against the ground. The force of static friction from the ground acts in the opposite direction, pushing you forward. In this case, friction is the very force that causes your forward motion.