Difficulty: Easy
Correct Answer: momentum
Explanation:
Introduction / Context:
Momentum encapsulates both how much matter an object has and how fast it moves, making it a fundamental conserved quantity in isolated systems. This question checks recognition of the standard term for “total motion.”
Given Data / Assumptions:
Concept / Approach:
Linear momentum p is defined by p = m * v. It is a vector quantity pointing in the direction of velocity. In the absence of external force, the total momentum of a system remains constant (principle of conservation of momentum).
Step-by-Step Solution:
Compute momentum: p = m * v. Interpretation: measures “quantity of motion.” Contrast with mass (amount of matter) and weight (gravitational force m * g). Impulsive force relates to abrupt force action; impulse J = ∫F dt equals change in momentum.
Verification / Alternative check:
Newton’s second law in impulse form: Δp = J. If no external impulse acts, Δp = 0, so momentum is conserved, reinforcing its role as “total motion.”
Why Other Options Are Wrong:
mass: property of matter only. weight: force due to gravity, not motion. impulsive force / impulse: interaction and its time integral, not a persistent state variable like momentum.
Common Pitfalls:
Confusing impulse (N·s) with momentum (also N·s in units) without noting impulse is an action, momentum a state.
Final Answer:
momentum
Discussion & Comments