原式0.25×1(-12)4-4÷1-(14)2×(-12)
=0.25×16-4-4=-4
故答案为:-4
质量为5kg的物体从高16m的地方由静止开始下落,着地时速度为16m/s,试求物体在下落过程中所受的平均阻力是多大?(g=10m/s2)
用abundant的适当形式填空。
1. Calcium is found most____in milk.
2. We have____evidence to prove his guilt.
3. They lead a life of____.