Recent content by dsm63

would i be right to assume that for [-b ± √(b2 - 4ac)]/2a a = 4.905 b = -20 c = 10.5 when using this i get t = 20 ±√19.7747 t = 24.44 or 15.55 this answer does not make sense? i think i have some something wrong.. using a calculator online i recieved t = .619 or 3.45s

Homework Statement 1. Neglecting the height of release, a ball is thrown vertically upwards at 20 m/s, find: d) time (s) that the projectile is at height 10.5 m. V1 = 20m/s a = -9.81m/s^2 d = 10.5m Homework Equations d = v1*t + 1/2 a(t^2) The Attempt at a Solution...