Speed–time graph of a bouncing ball (Exercise 2.8)उछलती गेंद का चाल–समय ग्राफ (अभ्यास 2.8)

NCERT Exercise 2.8 · interactive diagram

Parts and their functions

• First fall from 90 m (90 m से पहला पतन) — t = √(2h/g) = √(180/9.8) = 4.29 s; speed v = gt = 42 m s⁻¹.
• Collision with the floor (फ़र्श से टक्कर) — Loses one tenth of its speed: 42 → 37.8 m s⁻¹ (taken as instantaneous).
• Going up (ऊपर जाना) — Speed falls uniformly to zero in 37.8/9.8 = 3.86 s (at t = 8.14 s).
• Second fall (दूसरा पतन) — Takes another 3.86 s and hits the floor again at 37.8 m s⁻¹ at t = 12.0 s.

Original diagram drawn by Simple Learning Hub, based on NCERT Exercise 2.8. Report a mistake