The dimensions of momentum are

Step 1: Analyze the question We need the dimensions of momentum in terms of mass (M), length (L) and time (T).

Step 2: Concept Momentum = mass × velocity Velocity = displacement ÷ time, so its dimensions are LT⁻¹.

Step 3: Solution

• Mass: [M]
• Velocity: [L][T⁻¹] = LT⁻¹
• Momentum = M × LT⁻¹ = MLT⁻¹

Step 4: Check the options

• A. MLT: wrong, because time should be in the denominator.
• B. ML⁻¹T⁻¹: wrong, because length should have a positive power.
• C. MLT⁻¹: correct, and it matches our working.
• D. ML⁻¹T: wrong on both length and time.

As a cross-check, momentum has units kg·m/s, which gives M¹L¹T⁻¹. Impulse (force × time) gives the same units: N·s = kg·m·s⁻²·s = kg·m·s⁻¹.

Tip: Break each quantity into its basic units. Momentum is kg·m/s, so the mass and length have positive powers and the time has a negative power. Also remember that momentum and impulse have the same dimensions, which often appears in exams.