The relationship between the height h of the ball and the time t satisfies h(t)=-5$$t^{2}$$+$$v_0$$t . The initial velocity $$v_0$$ is 36 m/ s. How long does it take for the ball to return to its initial height?
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A6 s
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B6.4 s
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C7 s
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D7.2 s
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E7.6 s
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正确答案: D