Assertion (A): The coefficient of kinetic friction is always strictly less than the coefficient of limiting static friction. Reason (R): Once motion starts, the inertia of rest is broken and interlocking of surface irregularities is less effective. MCQ with Answer and Explanation

Explanation:
Energy density = energy/volume. Energy has dimensions [ML²T⁻²], volume [L³], so energy density = [ML²T⁻²]/[L³] = [ML⁻¹T⁻²]. Pressure = force/area = [MLT⁻²]/[L²] = [ML⁻¹T⁻²], identical. Force is [MLT⁻²], power [ML²T⁻³], momentum [MLT⁻¹]. This equivalence explains why pressure appears in Bernoulli's equation alongside kinetic/potential energy density. Memory aid: 'Pressure and energy density share dimensions [ML⁻¹T⁻²]'. This dimensional analysis question tests ability to derive and compare formulas, frequently appearing in competitive exams to assess conceptual depth.

Explanation:
I_E = I_C + I_B = 1 mA + 0.01 mA = 1.01 mA.

Explanation:
3×10⁸ m/s = 3×10⁵ km/s.