A bullet of mass 20 g is fired with velocity 200 m/s. Its momentum is MCQ with Answer and Explanation

Explanation:
Neglecting air resistance, total mechanical energy conserved.

Explanation:
Orbital velocity v = √(GM/r), where r is orbital radius from Earth's center. Thus v ∝ 1/√r. If r increases, v decreases. This follows from equating gravitational force to centripetal force: GMm/r² = mv²/r ⇒ v = √(GM/r). Higher orbits have slower speeds but longer periods. Memory aid: 'Higher orbit, slower speed' – counterintuitive but fundamental. This relationship is crucial for satellite motion questions in competitive exams. Always distinguish orbital velocity from escape velocity (which is √2 times orbital velocity at same radius).

Explanation:
Force (weight) is vertical (upward to support), displacement horizontal, angle 90°, cos90°=0, work = 0. No work against gravity because vertical height doesn't change. Energy spent is internal muscular effort, but physics work zero.