跳高运动员在跳高时总是跳到沙坑里或跳到海绵垫上,这样做是为了
A.减小运动员的动量变化
B.减小运动员所受的冲量
C.延长着地过程的作用时间
D.减小着地时运动员所受的平均冲力
CD
In relation to employment law:
(a) Explain why it is important to distinguish between contracts of service and contracts for services. (4 marks)
分解蒸发原理