代入数据求得a1=
| v20 |
| 2h |
| 122 |
| 2×6 |
根据牛顿第二定律:mg+f=ma1
f=ma1-mg=m(12-10)=2m
| f |
| mg |
| 2m |
| 10m |
(2)上升过程所用时间t1=
| v0 |
| a1 |
| 12 |
| 12 |
下落过程加速度a2=
| mg−f |
| m |
| 10m−2m |
| m |
下落过程所用时间t2 h+H=
| 1 |
| 2 |
| t | 22 |
得t2=
|
|
总时间 t=t1+t2=3s
答:(1)空气阻力与小球重力大小的比值为0.2.
(2)小球从抛出到落到地面所经过的时间t为3s.
| f |
| mg |
| v20 |
| 2h |
| 122 |
| 2×6 |
| f |
| mg |
| 2m |
| 10m |
| v0 |
| a1 |
| 12 |
| 12 |
| mg−f |
| m |
| 10m−2m |
| m |
| 1 |
| 2 |
| t | 22 |
|
|