题干

一架喷气式飞机的速度是声音在空气中传播速度的1.5倍,飞行高度为3060m,水平方向飞行.当你听到飞机在你头顶上方的轰鸣声时,抬头观看(不计抬头的时间),飞机已飞到你前方多远(水平距离)的地方?(声音在空气中的传播速度是340m/s)

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解:∵喷气式飞机的速度是声音在空气中传播速度的1.5倍,声音在空气中的传播速度是340m/s,
∴喷气式飞机的速度v喷=340m/s×1.5=510m/s.
∵飞机的飞行高度为3060m,声音在空气中的传播速度是340m/s,
∴根据速度公式v=
s
t
,得:

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    For Zack, the shave was more than just a way to fund lifesaving research. It was a way to honor his late brother, Taylor Frink.

    Taylor, a volunteer firefighter in North Carolina, was killed in a car accident last September. Before his passing, Taylor was an eager supporter of St. Baldrick's. He went bald(秃头)for the cause in 2015, supporting kids with cancer and raising money to find cures.

    As a local hero, Taylor was beloved by the community. When he died, more than 1, 000 people attended his funeral to pay their respects. Zack looked up to his brother and this was the reason why he decided to become a junior firefighter himself. They did everything together. Zack remembers.

    Zack knew his brother had planned to shave again in 2016, so without hesitation he decided to fill his shoes and registered to shave at the local St. Baldrick's event in Kinston, N. C.

    “He was always goodhearted, and I want to make my brother proud,” shares Zack.

    As part of Zack's kindnesses, he raised more than $ 1,000 for the St. Baldrick's Foundation primarily by selling T-shirts he designed. Leading up to the event, Zack also visited his city council, commissioner's office and challenged the local official department to get involved.

    “We are not going to let Taylor's name be forgotten. That is what I love about St Baldrick's,” says Jean Culbreth, volunteer event organizer. “Zack gets it. He gets that what he is doing is keeping his brother's name alive.”

    The day finally came and Zack took his seat under the clippers (剪具), not only to honor his brother but to help kids with cancer. It was a special moment for all, and by the end of the day the event had raised more than $ 22,000!