5. SKUPINA

Mentor: Matej Erjavec, prof.

Dijaki: Domen Ravnik

Miha Soklič

Martin Žmitek

Stanko Pintar

Datum: 19. 5. 2009

Naloga 1:

Ftr= 0,02N sin= h/s = 0,095m / 1,8m = 0,053s = 1,8m = 3°h = 9,5cm mv= 788g

Wp = m*g*h = 0,8kg*9,81m/s2*0,095m = 0,75J Atr = Ftr*s = ktr*Fn*s = ktr*m*g*cos*s = = 2,5*10-3*0,8kg*9,81m/s2*0,99*1,8 = 0,035J Wk = Wp – Atr = 0,75J – 0,035J = 0,715J Wk = mv½ 2

Iz dela poskušajte izpeljati kinetično energijo.

A=F s = m a s = m a ½a t2 = ½m a2 t2 = ½m v2

F s v2

Naloga 2:

Naloga 3:

h

= 2,7 kg/dm3

a = 10cm = 0,1mA = ?

c2 = (a/2)2 + (a/2)2 = 25 + 25 = 50c = 7,07cm

h = 7,07cm – 5cm = 2,07cm

V = a3 = 103 = 1000cm3 = 1dm3

m = *V = 2,7kg

Wp = AA = m*g*h = 2,7kg*9,81m/s2

*0,0207m = 0,55J