Question

Tóm tắt:

\(t_1\)=\(\dfrac{1}{3}\)t ; \(V_1\)= 12m/s

\(t_2\)=\(\dfrac{2}{3}\)t ; \(V_2\)= 9m/s

Tính \(V_{tb}\)= ? m/s

Answer 1

tính S1, S2

sau đó áp dụng v_tb=\(\dfrac{S_1+S_2}{t_1+t_2}\)

Answer 2

S₁=v₁t₁=12.\(\dfrac{1}{3}=4t\left(km\right)\)

S₂=v₂t₂=\(\dfrac{9.2}{3}=6t\left(km\right)\)

=>\(v_{tb}=\dfrac{S_1+S_2}{t_1+t_2}=\dfrac{4t+6t}{t}==\dfrac{10t}{t}=10\)(km/h)

Vậy_____________