Question

O minge de masa m=0.5 kg cade vertical si loveste o suprafata orizontala cu viteza v1=10m/s. Imediat dupa ce se loveste suprafata mingea are viteza v2=8m/s, orientata vertical in sus. Daca intercatiunea cu suprafata dureaza un timp deltat=2ms, forta F cu care mingea actioneaza asupra suprafetei are valoarea....

Answer 1

$F = \dfrac{\Delta p}{\Delta t} \\ \\ =\dfrac{m\cdot \Big[v_1-(-v_2)\Big]}{t}\\ \\ = m\cdot \dfrac{v_1+v_2}{t}\\ \\=0,5\cdot \dfrac{10+8}{0,002} \left[\mathrm{kg}\cdot \dfrac{\mathrm{m}/\mathrm{s}}{\mathrm{s}}\right] \\ \\ =500\cdot \dfrac{18}{2}= \boxed{4500\, \mathrm{N}}$