问题 选择题

弹射器竖直向上弹出一个小球,小球上升到的最大高度为h,从弹出点至落回到处的过程中,关于小球的位移和路程,下列说法正确的是 (   )

A.位移为,路程为

B.位移为,路程为

C.位移为,路程为

D.位移为,路程为

答案

答案:C

题目分析:位移是指从初位置到末位置的有向线段,所以此时物体的位移的大小是,路程是指物体所经过的路径的长度,此时的路程为, C正确.

阅读理解
阅读理解。
    Children in England mustn't work until they are 13. They need to have a work permit (许可)
to start working.
The jobs teenagers can doThe hours teenagers (13 and 14 year olds)
can work
    Delivering (送) newspapers
    Many teenagers will get up early to deliver
newspapers to houses in their local area before
going to school.They are known as Paperboys
or Papergirls.
    Babysitting
    Looking after young children in their home
while their parents have gone out for the evening
is a popular job for teenagers, as they get money
for watching children and television all at the
same time!
    Helping the Milkman
    From the age of 14 some teenagers help the
milkman deliver milk to houses. Other popular
jobs Working in a shop; Office work; Washing
cars; In a cafe or restaurant.
    School Days
    Not more than 2 hours in one day
during the following periods:
    Morning: 7 a.m.- start of school
    Evening: close of school-7 p.m.
    Saturdays: Up to 5 hours between
7 a.m.and 7 P.m. 
    Sundays: Up to 2 hours between
7 a.m.and 11 a.m.
    Term time: Up to 12 hours a week
(Including weekends)




1.In England how old do children have to be before they can work?
[ ]
A.15
B.14
C.10
D.13
2.Paperboys and Papergirls deliver newspapers ______.
[ ]
A.early in the morning
B.at noon
C.in the afternoon
D.in the evening
3.Teenagers in England can do all of the following except ______.
[ ]
A.work in an office
B.work in a night club
C.look after young children
D.deliver newspapers
4.How many hours a week many teenagers work during the term time?
[ ]
A.10
B.14
C.17
D.20
单项选择题