题干

科学家们研究发现,同一物体越靠近赤道,所受的重力越小;越靠近地球两极,所受的重力越大。一艘军舰从我国青岛港出发,前往位于赤道附近的亚丁湾执行护航任务,若军舰总质量保持不变,根据上述信息,比较军舰在青岛和亚丁湾两地海域所受浮力的大小,下列说法正确的是(   )

A:在亚丁湾所受浮力较小

B:在亚丁湾所受浮力较大

C:在两地所受浮力相等

D:不知两地海水密度是否一样,无法比较浮力大小

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A

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    Many people traveled to Las Vegas, Nevada last week for the 50th Consumer Electronics Show, or CES. The show is said to have the largest collection of new electronic devices in the world.

    The show had many examples of “smart home” devices. “Smart home” technology is designed to make life easier for people by letting computers control many things inside our homes. One such device actually begins working outside the home, when someone arrives and rings the doorbell.

    “When someone comes to your front door and rings the doorbell, the light can turn on immediately. I get a notification when I'm halfway around the world that someone came, and I can start talking to the person who's at my front door, and I can say, 'Oh, here let me let you in,' I can unlock the door for them very easily.” Said Vivint, a smart home service provider.

    One electronics maker launched a device that lets people see and interact with their animals when they are away. The device, from Petcube, lets you remotely watch and talk to your pet through a personal device, according to a company official. It can even give the pet a treat—if you approve and order it.

    For heating or cooling, there is a smart thermostat. This device can also send you a message if a big storm causes leaks of flooding. “We're trying to catch it with just a few drips before it becomes a real big problem,” said Mike Sale of iDevices.

    A concern for many homeowners is the possibility that someone else might find a way to attack these smart home devices. An official from Vivint said his company is sure that only owners of the home can gain use of information on the devices. Warren Katz from iDevices said his company employs engineers from the defense industry to help prevent hacking.