Which of the following is the dimension for impulse?

Analyze the question: Impulse is asked for in terms of its dimensions (M, L, T).

Concept: Impulse is the product of force and the time for which the force acts. It equals the change in momentum.

Impulse = F × t = Δ(mv)

Solution:

Method 1 (Force × time):

• Force = mass × acceleration = M × LT⁻² = MLT⁻²
• Impulse = MLT⁻² × T = MLT⁻¹

Method 2 (Change in momentum):

• Momentum = mass × velocity = M × LT⁻¹ = MLT⁻¹

Both methods give the same dimension: MLT⁻¹.

Checking the options:

• A. MLT⁻¹ matches our result.
• B. MLT⁻² is the dimension of force, not impulse.
• C. MLT has no physical meaning here.
• D. ML is incorrect.

Tip: Impulse and momentum have the same dimensions and the same units (N·s = kg·m/s). If you forget one, derive it from the other. Also remember that MLT⁻² is force, so multiplying by time lowers the power of T by one, giving MLT⁻¹.