1.
[tex]dane:\\v_{o} = 0\\h = 15 \ m\\g = 10\frac{m}{s^{2}}\\szukane:\\v = ?[/tex]
Z zasady zachowania energii:
[tex]E_{p} = E_{k}\\\\mgh = \frac{mv^{2}}{2} \ \ |\cdot\frac{2}{m}\\\\v^{2} = 2gh\\\\v = \sqrt{2gh}\\\\v = \sqrt{2\cdot10\frac{m}{s^{2}}\cdot15 \ m}} = \sqrt{300} \ \frac{m}{s} = 10\sqrt{3} \ \frac{m}{s}\\\\\underline{v = 17,32\frac{m}{s}}[/tex]
2.
[tex]dane:\\m = 750 \ g = 0,75 \ kg\\h = 15 \ m\\g = 10\frac{m}{s^{2}}\\szukane:\\W = ?\\\\W = E_{p} = mgh\\\\W = mgh\\\\W = 0,75 \ kg\cdot10\frac{m}{s^{2}}\cdot15 \ m\\\\\underline{W = 112,5 \ J}[/tex]
