Understanding Freebody Diagrams and Joint Forces

What is the primary purpose of a Freebody diagram?

• To visualize the 3D structure of a body

• To determine the speed of a moving object

• To calculate the forces around a stationary structure

• To measure the weight of a body

Which assumption is NOT made in the Freebody diagram model?

• The muscles act along their central axis in compression

• The bones are rigid rods

• The body is in equilibrium

• The joints are frictionless hinges

In a single leg stance, what fraction of the body weight is assumed to be the leg's weight?

• One third

• One fourth

• One fifth

• One sixth

How is the force of the abductors calculated?

• By subtracting the moment arm from the body weight

• By adding the body weight to the moment arm

• By multiplying the force of the abductors by the moment arm

• By dividing the body weight by the moment arm

What is the direction of the joint reaction force relative to the resolved vector?

• In the same direction

• Parallel to the body weight

• Perpendicular to the resolved vector

• In the opposite direction