Question

Answer 1

\(4\left(\dfrac{m}{s}\right)=14,4\left(\dfrac{km}{h}\right)\)

\(t'=s':v'=3:14,4=\dfrac{5}{24}h\)

\(\Rightarrow v=\dfrac{s'+s''}{t'+t''}=\dfrac{3+1,95}{\dfrac{5}{24}+0,5}\simeq7\left(\dfrac{km}{h}\right)\)

Answer 2

Đổi: \(4m/s=14,4km/h\)

\(t_1=\dfrac{S_1}{v_1}=\dfrac{3}{14,4}=\dfrac{5}{24}\left(h\right)\)

Vận tốc trung bình trên 2 quãng đường:

\(v_{tb}=\dfrac{S_1+S_2}{t_1+t_2}=\dfrac{3+1,95}{\dfrac{5}{24}+0,5}\approx7\left(km/h\right)\)