Question

Zad.2 Cialo spadlo z wysokosci 30m.Oblicz czas spadku i predkosci koncowa.Prosze o jak najprostsze rowiazanie :)

Answer 1

h = 30 m

g = 9,81 m/s² = 10 m/s²

V₀ = 0

t = ?

V = ?

h = g * t²/2

2h = g*t²

t² = 2h/g

t = √2h/g

t = √2*30 m/10 m/s²

t = √6 s²

t ≈ 2,45 s

 

h = a *t²/2    ; a = V/t

h = V/t*t²/2

h = V * t/2

2h = V * t

V = 2h/t

V = 2 *30 m/2,45 s

V = 60 m/2,45 s

V = 24,49 m/s

 

II sposób obl. V z zasady zachowania energii

Ep = Ek

m * g *h = m * V²/2

g * h = V²/2

2gh = V²

V = √2gh

V = √2 * 10 m/s²*30 m

V = √600 m²/s²

V ≈ 24,49 m/s