A.水平面对楔形木块的弹力增大 |
B.水平面对楔形木块的摩擦力不变 |
C.墙对球的弹力不变 |
D.楔形木块对球的弹力增大 |
A.10N,500N/m | B.10N,1000N/m |
C.20N,1000N/m | D.20N,500N/m |
A.弹簧a下端受的拉力为0.4N,b下端受的拉力为0.6N |
B.弹簧a下端受的拉力为1N,b下端受的拉力为1N |
C.弹簧a的长度变为7cm,b的长度变为4.5cm |
D.弹簧a的长度变为6.4cm,b的长度变为4.3cm |
A.G/L1 | B.G/L2 |
C.G/(L1-L2) | D.2G/(L1-L2) |
© 2017-2019 超级试练试题库,All Rights Reserved.