a)Gia tốc vật: \(a=\dfrac{v-v_0}{t}=\dfrac{36-21,6}{25}=0,576=0,16\)m/s2
Quãng đường chuyển động:
\(S=\dfrac{v^2-v_0^2}{2a}=\dfrac{36^2-24^2}{2\cdot0,576}=625km\)
b)\(v=36\)km/h=10m/s; \(v_0=21,6\)km/h=6m/s
\(S_1=\dfrac{v_1^2-v_0^2}{2a}=\dfrac{14^2-10^2}{2\cdot0,16}=300m\)
\(t_1=\dfrac{v_1-v_0}{a}=\dfrac{14-6}{0,16}=50s\)
c)\(v_2=\sqrt{v_0^2+2aS_2}=\sqrt{6^2+2\cdot0,16\cdot152}=9,2\)m/s
Thời gian đi: \(t_2=\dfrac{v_2-v_0}{a}=\dfrac{9,2-6}{0,16}=20s\)
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