A ball of mass 0.5 kg moving at 4 m/s strikes a wall and rebounds at same speed. Impulse imparted is MCQ with Answer and Explanation

Explanation:
Atomic diameter ~ 1 Å = 10⁻¹⁰ m. Nucleus is 10⁻¹⁵ m (femtometre). Atomic size determined by electron cloud. 10⁻⁶ m is typical cell size. 10⁻³ m is millimetre.

Explanation:
Pascal's law: F₁/A₁ = F₂/A₂ => F₂ = (A₂/A₁) F₁ = 10×20 = 200 N.

Explanation:
In uniform circular motion, speed is constant but velocity direction changes continuously, producing centripetal acceleration. Magnitude a = v²/r, direction always towards the center of the circle. This acceleration changes velocity direction without altering speed. Tangential acceleration would change speed, but here speed is constant. Formula derivation: From vector analysis of velocity change over small time interval. Exam tip: Remember 'centripetal' means 'center-seeking'; this concept is fundamental for rotational dynamics questions in competitive exams.