Time for to-and-fro: t = 2d/v ≥ 0.1 s ⇒ d ≥ vt/2 = 340×0.1/2 = 17 m. Minimum distance for brain to distinguish echo from original sound. Memory tip: 'd_min = v×persistence/2'. Application of sound reflection with human perception limit, common in competitive exam numericals.
Explanation:
Higher pressure raises boiling point, so water can reach temperatures above 100°C, cooking food faster. At high altitudes, pressure cooker compensates for lower atmospheric pressure.
A ball is dropped from a height 'h' and simultaneously another ball is thrown horizontally from the same height. Which ball will hit the ground first? (Neglect air resistance)
Explanation:
Vertical and horizontal motions are completely independent. Both balls have zero initial downward (vertical) velocity and both are subject to the same downward acceleration due to gravity (g). Since the vertical height (h) is the same, using h = ut + ½gt², time t = √(2h/g) applies equally to both. Thus, they hit the ground simultaneously.
No comments yet. Be the first to start the discussion!