根据短文内容，选择正确答案。

    Terrafugia Company has said that its flying car, named Transition, has successfully finished a 37- second test flight.

    On March 5th, 2009, at Plattsburgh International Airport in New York. The company's chief pilot, Phil Meteer, piloted the flying car.

    Transition is a two-seat airplane that can take off and land at airports as well as drive on roads.

    The company said that the flying car can travel at speeds up to 115 mph in the air, drive at highway speeds on the ground, and fold up (折叠）to fit in a garage (车库) 81 inches wide and 80 inches high.

Hospitals could use it to transport patients so as to avoid road traffic. It may start running on wheels, and when it gets to traffic lights it can fly overhead the lights and keep its way forward. So it's good news to avoid traffic problems and the traffic accidents.

But some people say this is a going airplane rather than a flying car, at least on the appearance. Anyway, we are happy for scientific-technical progress, what a fantastical world in the near future!

在汽车的使用和我们乘坐的过程中，里面运用了许多的物理知识，请结合所学物理知识举出两个例子并说明所运用到的物理知识．

例如：司机要通过打方向盘来改变汽车的运动方向﹣﹣力是改变物体运动状态的原因．

一光滑圆弧形的槽，槽底放在水平地面上，槽的两侧与坡度及粗细程度相同的两个斜坡aa’、bb’相切，相切处a、b位于同一水平面内，槽与斜坡在竖直平面内的截面如图所示．一小物块从斜坡aa’上距水平面ab的高度为2h处由静止沿斜坡滑下，并自a处进入槽内，到达b后沿斜坡bb’向上滑行，不考虑空气阻力,到达的最高处距水平面ab 的高度为h；接着小物块沿斜坡bb’滑下并从b处进入槽内反向运动，沿斜坡aa’向上滑行到达的最高处距水平面ab 的高度为 （ ）

在等差数列$\left\{a_n\right\}$中，$3\left(a_3+a_5\right)+2\left(a_7+a_{10}+a_{13}\right)=48$,则等差数列$\left\{a_n\right\}$的前13项的和为（   ）