A satellite is orbiting close to Earth's surface. Its orbital speed is (g = 10 m/s², R = 6400 km) MCQ with Answer and Explanation

Explanation:
L = r × p: [L][MLT⁻¹] = [ML²T⁻¹]. Same as Planck's constant. Memory tip: 'Angular momentum: [ML²T⁻¹]; action quantities share dimensions'. Dimensional analysis frequently tested in competitive exams.

Explanation:
For perpendicular forces: R = √(F₁² + F₂²) = √(9 + 16) = √25 = 5 N. Pythagorean theorem applies for vector addition at 90°. Memory aid: '3-4-5 triangle for perpendicular forces'. Basic vector addition problem testing magnitude calculation, common in mechanics sections of competitive exams.

Explanation:
For equal distances: average speed = total distance/total time = 2d/(d/v₁ + d/v₂) = 2v₁v₂/(v₁+v₂). This is harmonic mean, not arithmetic. Memory tip: Equal distances ⇒ harmonic mean of speeds; equal times ⇒ arithmetic mean. Frequently tested kinematics concept distinguishing average speed calculation methods.