Question

Me ajudem, por favor! ​(clique na foto)

Answer 1

usar a energia mecânica:

$E_M=\frac{1}{2}mv^2 +mgh$

pela conservação da energia:

$\frac{1}{2}mv_i^2 +mgh_i=\frac{1}{2}mv_f^2 +mgh_f$

a)

$\frac {1}{2}m.0^2 +35.10.5=\frac{1}{2}.35.v_f^2 +35.10.1,8\\\\1750=\frac{1}{2}.35.v_f^2 +630\\\\v_f^2=\frac{(1750-630).2}{35} =64\\\\v_f=\sqrt{64} =8 \ m.s^-^1$

b)

$\frac {1}{2}mv_i^2 +mgh_i=\frac{1}{2}mv_f^2 +mgh_f\\35.10.5=\frac{1}{2}.35.v_f^2\\v_f=\sqrt{\frac{3500}{35} } =10 \ m.s^-^1$