1.单选题- (共1题)
2.选择题- (共3题)
Do you love Beats headphones, True Religion jeans, and UGG shoes? These are some of the most popular brands (牌子) around. They are also expensive. But some experts say they are not much better than cheaper brands.
For example, Jim Wilcox works for Consumer Reports. He tested all kinds of headphones. He says that $80 Koss Pro headphones provide basically the same quality (质量) and comfort as Beats. So why do people pay twice or even 10 times as much for the hottest brands?
Experts say it's because fashionable, expensive brands send a message. Brands say “I belong” or “I can afford it.”
Some people think that expensive brand names are worth the price. They say that some designer clothes really are top quality and that they last longer than cheaper brands. Some teenagers choose to wear popular brands because these brands make them feel good about themselves.
Alexandra Allam, 17, likes to buy brand-name products. “I'd rather spend the extra money to get something I know I'll be satisfied with,” she says. Her friend Emmy Swan agrees, saying “As long as you can afford it, it seems reasonable to buy what you want.” But not all teenagers agree. “Spending hundreds of dollars for designer sunglasses is stupid and unreasonable,” says Daniel Steinbrecher, 16. “It's fake (假的) happiness.”
People who are against wearing expensive brand names say that many designer brands aren't any better. “It's wasteful to buy things just because they are popular,” says Edmund Williams, 15. “You'll feel better if you buy things because you like them. If you have extra money to spend, it would be better to give it to people in need.”
3.多选题- (共7题)
A.宇航员仍受重力的作用 |
B.宇航员受力平衡 |
C.宇航员所受重力等于所需的向心力 |
D.宇航员不受重力的作用 |
A.当火车以速率v0行驶时,火车的重力与支持力的合力方向一定沿水平方向 |
B.当火车的速率v>v0时,火车对外轨有向外的侧向压力 |
C.当火车的速率v>v0时,火车对内轨有向内的挤压力 |
D.当火车的速率v<v0时,火车对内轨有向内侧的压力 |

A.小球通过最高点时的最小速度![]() |
B.小球通过最高点时的最小速度vmin=0 |
C.小球在水平线ab以下的管道中运动时,内侧管壁对小球一定无作用力 |
D.小球在水平线ab以上的管道中运动时,外侧管壁对小球一定有作用力 |

A.在最高点小球的速度水平,小球既不超重也不失重 |
B.小球经过与圆心等高的位置时,处于超重状态 |
C.盒子在最低点时对小球弹力大小等于2mg,方向向上 |
D.该盒子做匀速圆周运动的周期一定等于![]() |

A.绳a对小球拉力不变 |
B.绳a对小球拉力增大 |
C.小球可能前后摆动 |
D.小球不可能在竖直平面内做圆周运动 |

A.若拉力突然变大,小球可能沿轨迹Pb做离心运动 |
B.若拉力突然变小,小球可能沿轨迹Pb做离心运动 |
C.若拉力突然消失,小球可能沿轨迹Pa做离心运动 |
D.若拉力突然变小,小球可能沿轨迹Pc做近心运动 |

A.从a点到b点的过程中A的向心加速度越来越大 |
B.从a点到b点的过程中B对A的摩擦力越来越小 |
C.在a点时A对B压力等于A的重力,A所受的摩擦力达到最大值 |
D.在通过圆心的水平线以下各位置时A对B的压力一定大于A的重力 |
4.解答题- (共1题)
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【1】题量占比
单选题:(1道)
选择题:(3道)
多选题:(7道)
解答题:(1道)
-
【2】:难度分析
1星难题:0
2星难题:0
3星难题:0
4星难题:0
5星难题:0
6星难题:2
7星难题:0
8星难题:7
9星难题:0