Question

help please!!.......

Answer 1

v²=vo²-2ghm<=>0=vo²-2ghm=>hm=vo²/2g

v=vo-gtu<=>0=vo-gtu=>tu=vo/g

t∈(tu-1 ;tu)

t₁=tu-1=>x₁=vo(tu-1)-g(tu-1)²/2

t₂=tu=>x₂=votu-gtu²/2

Δx=x₂-x₁=votu-gtu²/2-vo(tu-1)+g(tu-1)²/2=votu-gtu²/2-votu+vo+gtu²/2+g/2-2gtu=vo+g/2-2gtu=vo+g/2-2vo=-vo+g/2

Δx=hm/2<=>-vo+g/2=vo²/4g<=>-2vo+g=vo²/2g |*2g<=>vo²+4vog-2g²=0

Δ=16g²+8g²=25g²=2500

v₁=(-40-50)/2=-45 m/s <0 N.C.

v₂=(-40+50)/2=5 m/s

vo=v₂=5 m/s

tu=vo/g=5/10=0,5 s

hm=vo²/2g=5²/20=25/20=1,25 m