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    The fixed-gear bicycle has had new popularity as the interest in bicycles has increased. The simple construction of this vehicle makes it a predecessor of the more typical freewheel bicycles used today. The bicycle is constructed with a rear sprocket (or gear) and a sprocket in front of it  that  is fixed to the rear wheel. A fixed gear means there is no freewheel, so the rear sprocket is attached directly to the rear wheel. When the wheel turns, then the rear sprocket (and therefore the front sprocket and pedals) turns. It is not possible for the rider to coast on such a bike. In early bicycle racing, the fixed-gear bicycle was used to set speed information for a specific track at a specific event. These bicycles also have no brakes, making it difficult to make sudden speed changes, which is intended to improve their safety. In the following video, a person is attempting to break the speed record on a fixed-gear bicycle:
    ::随着对自行车的兴趣增加,固定轮胎自行车获得了新的受欢迎程度。 这辆车的简单构造使它成为今天使用的更典型的免费自行车的前身。 自行车是用后轮螺旋( 或齿轮) 和前面的螺旋桨建造的, 前面的螺旋桨固定在后轮上。 固定齿轮意味着没有自由轮, 因此后轮螺旋将直接附在后轮上。 当轮转动时, 后轮螺旋( 因而是前轮螺旋和踏板) 转动。 骑手不可能骑在这样的自行车上海岸。 在早期的自行车赛车中, 固定齿轮自行车被用来为特定赛道设定速度信息。 这些自行车也没有刹车, 因而难以突变速度变化, 目的是提高它们的安全性。 在接下来的录像中, 一个人试图在固定轮自行车上打破速度记录 :

     

     

    Here is the situation:
    ::情况如下:

    • The sprocket assembly of a bike consists of a front gear and a back gear connected by a chain.
      ::自行车的螺旋状组装由前装件和后装件组成,后装件由链连接。
    • The back gear is attached to the back wheel.
      ::后车架附在后车轮上
    • The front gear is 9 inches in diameter.
      ::前置装备直径为9英寸
    • The back gear is 6 inches in diameter.
      ::后背装备直径为6英寸
    • The back wheel is 26 inches in diameter.
      ::后轮直径26英寸

    In cycling, if we know how fast the wheels turn, then we’ll know how fast the rear sprocket turns. If we know how fast the rear sprocket turns, then we’ll know how fast the chain moves. If we know how fast the chain moves, then we’ll know how fast the front sprocket turns. If we know how fast the front sprocket turns, then we’ll know how fast the pedals turn. The rate at which the pedals turn is known as the cadence. Since the system turns, it has an angular speed and a linear speed. The angular speed is the rate at which the pedals turn, described in units such as revolutions per second. The linear speed is the speed at which some point on the edge of the sprocket travels, in units such as meters per second.
    ::在自行车中,如果我们知道车轮转速有多快,那么我们就会知道车尾螺旋转速多快。如果我们知道后螺旋桨转速多快,我们就会知道车尾螺旋转速多快。如果我们知道车尾螺旋转速多快,我们就会知道车尾螺旋转速多快。如果我们知道车尾螺旋转速多快,我们就会知道车尾螺旋转速多快。自系统转动以来,车尾螺旋形速度和直线速度多快。角速度是车尾螺旋转速的速,以诸如每秒革命的单位描述。线性速度是螺旋螺旋螺旋桨边缘的某一点移动速度,以每秒米等单位的速度计算。

    For this project, you will determine how fast the bike is traveling if the cyclist is peddling at 1.2 revolutions per second.
    ::对于这个项目,你将决定自行车的行驶速度, 如果骑自行车的骑手以每秒1.2次的翻车速。

    1. Find the linear speed of a point on the sprocket attached to the pedal. (Use the diameter of the front gear.)
      ::在与踏板相连的螺旋桨上找到一个点的线性速度。 (使用前齿的直径。 )

    The chain moves at this calculated linear speed.  Also, a point on the gear sprocket attached to the wheel travels at this linear speed.
    ::链条以这种计算线性速度移动。 另外, 与轮子相连的齿轮上的一个点会以这种线性速度移动。

    1. Calculate the angular speed of the gear attached to the wheel.
      ::计算与轮子相连的齿轮角速度。

    The wheel travels at this calculated angular speed.  
    ::车轮以这个计算角速度行驶

    1. Calculate the linear speed of a point on the back wheel to determine how fast the bicycle is traveling. 
      ::计算后轮一个点的线性速度,以确定自行车的行驶速度。

     

    Resources:
    ::资源:

    "Bike Wheel Diagram Angular and Linear Velocity ." GeoGebra. N.p., 13 Dec. 2013. Web. 02 Apr. 2016.
    ::GeoGebra.N.p.,2013年12月13日,2016年4月2日,Web.02。

    "Fixed Gear Conversions." Fixed Gear Bicycles for the Road. N.p., n.d. Web. 02 Apr. 2016.
    ::"固定的Gear转换" 固定的Gear自行车 路路。 N. p.,n. d. Web. 02 Apr. 2016年4月2日。

    "Roller Speed Record Attemp." YouTube. N.p., n.d. Web. 02 Apr. 2016.
    ::2016年4月2日,YouTube.N.p.,n.d. Web. 02 Apr.

    "Video: Rider Attempts to Hit 100mph by Bicycle." The Telegraph. Telegraph Media Group, n.d. Web. 02 Apr. 2016.
    ::“Video:骑手试图用自行车击打100米。”《电报》,电报媒体集团,n.d.Web.02 Apr.2016年4月2日。

    Weyland, Jocko. "Unstoppable." The New York Times. The New York Times, 28 Apr. 2007. Web. 02 Apr. 2016.
    ::《纽约时报》,《纽约时报》,2007年4月28日,2007年4月28日。