A particle is subjected to forces of [img=18x22]1803a46e41745d3.png[/img], [img=18x22]1803a46e4a7b58d.png[/img], ¼ and [img=20x22]1803a46e54cefd0.png[/img], and the resultant of these forces is [img=78x36]1803a46e5d7bb8f.png[/img]. Which statement is correct?
A: The moving direction of the particle must be the same as that of the resultant force [img=14x19]1803a46e65bb7b5.png[/img].
B: The greater the resultant force [img=14x19]1803a46e6dfa97e.png[/img], the greater the speed of the particle.
C: The greater the resultant force [img=14x19]1803a46e772e05b.png[/img], the greater the acceleration of the particle.
D: The acceleration direction of the particle may or may not be the same as that of the resultant force [img=14x19]1803a46e772e05b.png[/img].
A: The moving direction of the particle must be the same as that of the resultant force [img=14x19]1803a46e65bb7b5.png[/img].
B: The greater the resultant force [img=14x19]1803a46e6dfa97e.png[/img], the greater the speed of the particle.
C: The greater the resultant force [img=14x19]1803a46e772e05b.png[/img], the greater the acceleration of the particle.
D: The acceleration direction of the particle may or may not be the same as that of the resultant force [img=14x19]1803a46e772e05b.png[/img].
举一反三
- X={a,b,c,e}, Y={d,e,f}, 则 X x Y 的子集有[img=20x18]17e436c2da798b3.jpg[/img]个，但是其中 X 到 Y 的映射只有[img=14x19]17e436c2e80db16.jpg[/img]个。
- 设X为随机变量，且E(X)= −1,Var(X)=3，则[img=136x31]1803b3be69ca3f3.png[/img] A: 18 B: 9 C: 30 D: 14
- A particle is described by the wavefunction [img=125x28]180380acf324ab6.png[/img] . The probability of finding it anywhere on the positive x axis (i.e., on the interval 0<x<∞) is equal to A: [img=9x43]180380acfada5ef.png[/img] B: [img=25x47]180380ad0313e37.png[/img] C: [img=9x43]180380ad0b681d3.png[/img] D: it depends on the value of [img=11x19]180380ad142db4c.png[/img]
- 下列4个集合中是空集的是（） A: ｛x|[img=18x22]1802f060e2f728f.png[/img]+1=0｝ B: ｛x|[img=18x22]1802f060e2f728f.png[/img]<-x｝ C: ｛x|[img=18x22]1802f060e2f728f.png[/img]=0｝ D: ｛x|[img=18x22]1802f060e2f728f.png[/img]-1=0｝
- 下列4个集合中是空集的是（） A: ｛x|[img=18x22]1803d021d498831.png[/img]+1=0｝ B: ｛x|[img=18x22]1803d021d498831.png[/img]<-x｝ C: ｛x|[img=18x22]1803d021d498831.png[/img]=0｝ D: ｛x|[img=18x22]1803d021d498831.png[/img]-1=0｝