The position-time graph of a particle is a parabola opening upwards. This indicates that the particle has: MCQ with Answer and Explanation

Explanation:
Escape velocity v_e = √(2GM/R). Mass M = density ρ × volume = ρ×(4/3)πR³. Thus v_e = √(2Gρ×4/3πR³ / R) = √(8GρπR²/3) ∝ R√ρ. Given same density and R_planet = 2R_earth, v_e ∝ R, so v_e_planet = 2 × 11.2 = 22.4 km/s. This derivation shows escape velocity scales linearly with radius for constant density. Memory tip: v_e ∝ √(M/R) and M ∝ R³ for constant ρ, so v_e ∝ R. Such proportional reasoning questions test conceptual grasp of gravitation formulas in competitive exams without heavy calculation.

Explanation:
Geostationary satellites orbit in Earth's equatorial plane with period matching Earth's rotation period (24 hours), so they appear stationary relative to ground. Orbital radius is about 42,000 km from Earth's center. Memory tip: 'Geostationary: T=24 h, equatorial orbit, fixed position; used for communication/weather satellites'. This standard result is frequently tested in competitive exams. Always recall that geostationary is a special case of geosynchronous (same period) with zero inclination; competitive exams often compare low orbit (84 min) vs geostationary (24 h) periods.

Explanation:
1 amu = 1.6605 × 10⁻²⁷ kg, using E=mc² gives about 931.5 MeV. Used in nuclear binding energy calculations. Not eV, but MeV. Very large energy per nucleon.