一水平传送带以2.0m/s的速度顺时针传动，水平部分长为2.0m．，其右端与一倾角为θ=37°的光滑斜面平滑相连，斜面长为0.4m，一个可视为质点的物块无初速度地放在传送带最左端，已知物块与传送带间动摩擦因数μ=0.2，试问：

    What do you think the future will be like? Here are some answers from some students.

    Mary: Everyone will have a computer at home. There will also be many machines in the future. Then people will work only two or three days in a week.

    Jack: The weather in the future will be very hot. People can't live on the earth. They will have to look for (寻找) another planet to live on.

    Linda: I think the life in the future will be nice. There will be a lot of flowers and trees. And cities will look like parks.

    Henry: Every family will have a family doctor, so people will be seldom ill (很少生病) They will live to 120 years old.