题干

如图所示,足够长的水平传送带以v0=4m/s的速度匀速运行。t=0时,在最左端轻放一质量为m的小滑块,t=4s时,传送带以1 m/s2的加速度减速停下。已知滑块与传送带之间的动摩擦因数μ=0.2。关于滑块相对地面运动的速度v(向右为正)、滑块所受的摩擦力f(向右为正)、滑块所受的摩擦力做功的功率的值P、滑块与传送带间摩擦生热Q的图像正确的是(    )


A:      

B:

C:      

D:

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C

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    Robot are about to enter our lives. From doing housework, entertaining and educating our children, to looking after the elderly, scientists say we will soon be welcoming robots into our homes and workplaces.

    Researchers believe we are on the cusp (过渡点) of a robot revolution that will mirror the quick growth of the computer revolution. They are developing new laws for robot behavior, and designing new ways for humans and robots to communicate.

    “I think robots will change who we are, just as eyeglasses and fire changed who we were before, says Rodney Brooks, a director of the MIT Computer Science and Artificial Intelligence Laboratory.

    Some ideas and technologies may sound like science fiction, but they are fast becoming science fact. Robots scientists invented are already beginning to perform everyday tasks like cleaning our floors. The latest types from Japan are able to help the elderly to get out of bed or get up after a fall. They can also remind them when to take medication (药物), or even help wash their hair.

    “Robot now are not human-like. For example they are things like automatic (自动的) beds and wheelchairs,” says Prof Hiroshi Ishiguro at Osaka University, Japan. He believes the time is coming when robots start looking less like machines, and more like us. “In the near future we are going to use more human-like robots. I really think so, says Prof Ishiguro.

    Prof Maja Mataric at the University of Southern California agrees. “I'm very excited about the fact that today we are trying to make robots that look like human beings,” she says.

    “I believe we love robots because they're reflections (反映) of ourselves,” says Ken Goldberg, director of the Berkeley Center for New Media at the University of California at Berkeley.

    “Robots could be used in education, learning, and healthcare, where social support is important,” says Dr. Cynthia Breazeal, director of the Personal Robots Group at MIT.