Question

com aceleração de 5m/s² calcule b) vi = 4 km/h vf = 28 km /h ti = ? em min tf = 6,2 h

Answer 1

$\boxed{\begin{array}{l}\sf v_i=4 km/h\div3,6=1,11m/s\\\\\sf 6,2h\cdot3600=22320~s\\\\\sf 28~km/h\div3,6=7,77\\\\\sf a=\dfrac{v_f-v_i}{t_f-t_i}\\\\\sf 5=\dfrac{7,77-1,11}{22320-t_i}\\\\\sf111600-5t_i=6,66\\\\\sf t_i=\dfrac{111600-6,66}{5}=22318,68s\div3600=6h~11min~24s \end{array}}$