Newton's first law defines: MCQ with Answer and Explanation

Explanation:
The effective acceleration due to gravity at latitude lambda is g' = g - R * w^2 * cos^2(lambda), where w is angular velocity. At the equator, lambda = 0, so cos(0) = 1. This subtracts the maximum outward centrifugal acceleration (Rw^2) from g. At the poles, lambda = 90, centrifugal effect is zero. Thus, g is minimum exactly at the equator.

Explanation:
For constant pressure (isobaric) process, work done by gas W = PΔV, where ΔV is change in volume. This derives from mechanical work W = F·d and pressure P = F/A, so F = PA, and dV = A·d, thus W = P·dV. Option D Δ(PV) applies to other contexts like enthalpy. Memory tip: 'Isobaric work = P times volume change'. This fundamental thermodynamics result is frequently used in first law applications. Competitive exams often combine this with ideal gas law for numerical problems; always verify process constraints (constant P here).

Explanation:
H = I² R t = 4 × 10 × 60 = 2400 J.