Biomechanics session 1 recap Quiz chinese)(

运动学的主要研究对象是什么？

• 力的研究

• 运动的研究

• 能量的研究

• 质量的研究

Answer explanation

The main research object of kinematics is the study of motion. It focuses on describing how objects move, including their speed, velocity, and acceleration, without considering the forces that cause the motion.

以下哪项是标量量?

• 速度

• 力

• 速度（矢量）

• 位移

Answer explanation

Speed is a scalar quantity as it only has magnitude and no direction. In contrast, force, velocity, and displacement are vector quantities, which have both magnitude and direction.

质心 (COM) 需要位于 (a)   之上以保持稳定性。

• 接触点

• 支撑基底 (BoS)

• 重心 (CoG)

• 地面高度

Answer explanation

The center of mass (COM) must be above the Base of Support (BoS) to ensure stability. If the COM is outside the BoS, the object is likely to tip over.

根据牛顿的第三运动定律，每一个作用力会发生什么？

• 会有一个相等且相反的反应

• 没有反应

• 会有一个延迟反应

• 会有一个成比例的反应

Answer explanation

According to Newton's third law of motion, for every action, there is an equal and opposite reaction. This means that forces always occur in pairs, with one force acting in one direction and the other force acting in the opposite direction.

抛体运动的最佳角度是多少？

• 60度

• 30度

• 90度

• 45度

Answer explanation

The optimal angle for projectile motion, which maximizes the range, is 45 degrees. This angle balances the vertical and horizontal components of the launch, allowing for the greatest distance traveled.

肌肉力学中的长度-张力关系指的是什么？

• 肌肉纤维的类型

• 肌肉的长度影响产生的力量

• 肌肉收缩的速度

• 肌肉的能量消耗

Answer explanation

The length-tension relationship in muscle mechanics indicates that the force a muscle can produce is influenced by its length. Optimal overlap of actin and myosin filaments occurs at certain lengths, maximizing force production.

以下哪项是定性分析的例子？

• 计算行驶的距离

• 测量跑步者的速度

• 观察运动中的协调性

• 计算跳跃的次数

Answer explanation

Qualitative analysis focuses on observing qualities rather than measuring quantities. 'Observing coordination in motion' assesses performance characteristics, while the other options involve numerical measurements.

拉伸-缩短循环（SSC）与 (a)   有关。

• 线性运动

• 分段旋转

• 静态平衡

• 肌肉疲劳

Answer explanation

The stretch-shortening cycle (SSC) enhances performance in activities involving segmented rotation, as it utilizes elastic energy during muscle contractions, improving efficiency in rotational movements.

Match the following descriptions with their corresponding concepts of angular momentum.

• The rate at which an object moves in a straight line

• The speed of an object in a straight line

• The quantity of rotation of an object

• The rotational motion of an object

• The total path length traveled by an object

• The distance traveled by an object

• The effect of a force on an object in motion

• The force applied to an object

Answer explanation

Angular momentum refers to the rotational motion of an object, which depends on its mass, shape, and speed of rotation. The other options describe linear motion or force, not the concept of angular momentum.

以下哪个是运动学变量？

• 加速度

• 力

• 位移

• 速度

Answer explanation

Kinematic variables describe motion without considering forces. Acceleration, displacement, and velocity are all kinematic variables. However, the question incorrectly identifies acceleration as the only correct answer, while displacement and velocity are also valid.