Question

Cele două probleme
Mulțumesc

Answer 1

98.

y1=h-gt^2/2

y2=v0t-gt^2/2

y1=y2=>h-gt^2/2=v0t-gt^2/2<=>h=v0t=>t=h/v0=40/20=2 s

y1=40-10•4/2=40-20=20 m

v1=gt=10•2=20 m/s

v2=vo-gt=20-2•10=20-20=0 m/s

99.

v^2=vo^2-2gh'<=>0=64-20h'=>h'=3,2 m

hmax=h+h'=10+3,2=13,2 m

a=x-h=13-10=3 m

va^2=vo^2-2ga=64-60=4=>va=2 m/s

b=hmax-x=13,2-13=0,2 m

v=va-gt1<=>0=2-10t1=>t1=0,2 s

va'^2=2gb=4=>va'= 2 m/s

va'=vo'+gt2<=>2=0+10t2<=>t2=0,2

T=t1+t2=0,2+0,2=0,4 s