[tex]a)\\F = 2 \ N\\m = 0,5 \ kg\\\\a = \frac{F}{m} = \frac{2 \ N}{0,5 \ kg} = 4\frac{N}{kg} = 4\frac{m}{s^{2}}[/tex]
[tex]b)\\F = 10 \ N\\a = 4\frac{m}{s^{2}} = 4\frac{N}{kg}\\\\m = \frac{F}{a} = \frac{10 \ N}{4\frac{N}{kg}} = 2,5 \ kg[/tex]
[tex]c)\\a = 20\frac{m}{s^{2}} = 20\frac{N}{kg}\\m = 4 \ kg\\\\F = m\cdot a = 4 \ kg\cdot20\frac{N}{kg} = 80 \ N[/tex]
