Question

Em cảm ơn nhiều :3

Answer 1

Bài 12:

\(\left\{{}\begin{matrix}v=\dfrac{s}{t}=\dfrac{25}{10}=2,5\left(\dfrac{m}{s}\right)\\v'=\dfrac{s'}{t'}=\dfrac{100-25}{15}=5\left(\dfrac{m}{s}\right)\\v_{tb}=\dfrac{S}{t+t'}=\dfrac{100}{10+15}=4\left(\dfrac{m}{s}\right)\end{matrix}\right.\)

Bài 13:

\(v_{tb}=\dfrac{s+s'}{t+t'}=\dfrac{vt+v't'}{t+t'}=\dfrac{30t+120t}{3t}=50\left(\dfrac{km}{h}\right)\)

Answer 2

vtb=s+s′t+t′=vt+v′t′t+t′=30t+120t3t=50(kmh)