Kinesiology

Unit ll Objectives

1. Kinetics is force. Kinematics is the time, space, and mass.

2. Linear forces result when two or more forces are acting along the same line. Ex: two people pulling a boat with the same rope in the same direction. Parallel forces occur in the same plane and in the same or opposite direction. Ex: three point pressures of bracing. Concurrent forces are two or more forces must act on a common point but most pull or push in different directions. Ex: two people pushing a desk up and over moving in a diagonal direction. Resultant force is the overall effect of these two different forces lies somewhere in between. Force couple is when two or more forces act in different directions, resulting in a turning effect.

3. Torque, also know as moment of force, is the ability to force or produce rotation around the axis

4. Torque is also the amount of force needed by a muscle contraction to cause rotary joint motion.

5. Axis aka fulcrum is the fixed point around which the lever rotates. Force aka effort is what causes the lever to move (usually muscular). Resistance aka the load, must be overcome for motion to occur can include the weight of the part being moved, the pull of gravity on the part, or an external weight being moved by the body part. arm: FA & RA. FA is the force arm, this is the distance between the force and the axis. RA is the resistance arm, this is the distance between the resistance and the axis.

6. First-class lever is when the axis is located between the force and the resistance. This lever is for balance. Ex: two loads (F and R) are balanced on the shoulders. The head moving on the neck is also a first-class lever. Second-class lever is when the resistance is in the middle with the axis at one end and the force is at the other end. This lever is for power. Ex: a wheelbarrow- the wheel at the front end is the axis, the wheelbarrow contents are the resistance, and the person pushing the wheelbarrow is the...