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Answer 1

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½âµÃ${t}_{B}=\sqrt{\frac{2{L}_{B}}{{a}_{1}}}=\sqrt{\frac{2¡Á0.9}{5}}s=0.6s$
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3sÄÚBͨ¹ýµÄλÒÆ$x¡ä=\frac{{v}_{B}^{2}}{2{a}_{2}}=\frac{9}{2¡Á1}m=4.5m$
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½âµÃ$t=\frac{5}{12}s$
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