Zad. 3
Ep = mgh
Względem podłogi:
Ep = 3kg · 10[tex]\frac{m}{s^2}[/tex] · 0,5m = 15J
Względem ziemi:
h = 3m + 0,5m = 3,5m
Ep = 3kg · 10[tex]\frac{m}{s^2}[/tex] · 3,5m = 105J
Zad.4
Ek = [tex]\frac{mv^2}{2}[/tex] / · 2
2Ek = [tex]mv^2[/tex] / : [tex]v^{2}[/tex]
m = [tex]\frac{2Ek}{v^2}[/tex]
0,5kJ = 500J
m = [tex]\frac{2*500J}{(10\frac{m}{s})^2 }[/tex] = [tex]\frac{1000J}{100\frac{m^2}{s^2} }[/tex] = 10kg
