一个重20N的物体，受到20N竖直向上的拉力时，该物体（　　）

阅读理解

    He's always the first to arrive at school in the morning and the last to leave. He's always asked to answer the teachers' questions and he's always in first place in his class and in the whole school.

    Aron Anderson is in a class of his own — in fact, he's the only pupil in his school. The ten-year-old boy studies in this farthest primary school in Britain. Whether he likes it or not, Aron gets the most attention of his teachers all the time.

    During the school day, he has two classrooms, a music room and a library all to himselfAnd between classes and after school, he has the whole playground with its slides (滑梯), swings and basketball court.

    One problem, of course, is that although he loves football, he has no other friends to play with. He also becomes one of the most expensively educated children in the UK.

    Aron's father Ewan is a 43-year-old fisherman who sometimes spends days at the sea. His mother Denise works in the island shop. She is also a firefighter.

    The island used to have a senior high school and a farm, but they were both closed with many families leaving. “I just wish we could go back ten years. There were lots of children and the older children used to help the younger ones at school,” Aron's mother said.