Question

Înălțimea ?.............

Answer 1

h=gt₁²/2=10t₁²/2=5t₁²

h=ct₂

T=t₁+t₂

5t₁²=ct₂<=>5t₁²=330t₂ |:5=>t₁²=66t₂

T=t₁+t₂ =>t₂=T-t₁

t₁²=66t₂<=>t₁²=66(T-t₁)<=>t₁²=66*T-66t₁<=>t₁²+66t₁-528=0

Δ=4356+2112=6468

t₁,₂'=(-66±80,42)/2

t₁'=(-66+80,42)/2=14,42/2=7,21 s

t₂'=(-66-80,42)/2<0=> N.C.

t₁=t₁'=7,21 s

t₂=T-t₁=8-7,21=0,79 s

h=ct₂=330*0,79=260,7 m