Mechanics Study Notes Quiz

Mechanics Study Notes

• Kinetics is the study of forces that cause motion.
• Machines provide a force advantage when lifting heavy objects.
• A lever system's components are force, axis, resistance, and fulcrum.
• Lever classes: Different lever classes (first, second, and third) have varying mechanical advantages based on the relative positions of the axis, force, and resistance. A lever provides a mechanical advantage if the force arm is longer than the resistance arm.
• An example of a lever system can be seen in the second image; a longer force arm produces a greater mechanical advantage. Therefore, moving the axis closer to the resistance will decrease the mechanical advantage.
• Third-class levers are beneficial for speed & range of motion (ROM).
• Torque is force applied at a distance from a rotational axis. Increasing the distance from the axis of rotation increases torque.
• The linear velocity of motion from angular motion is greater with a larger radius. Therefore a larger radius increases velocity.
• Newton's First Law of Motion (Inertia): A body in motion stays in motion or a body at rest stays at rest unless acted upon by an outside force.
• Momentum and inertia are not the same. Momentum considers both mass and velocity.
• Momentum is calculated by multiplying mass times velocity. Greater momentum results in greater resistance to change in motion. Person 3 has the greatest momentum, and therefore is the most resistant to change in motion and is least likely to fall down. Person 3 is the most resistant to change in motion and is least likely to fall.
• Ground Reaction Force is important for jumping and other movements. Without adequate Ground Reaction Force, a jump will be lower.
• Rolling friction provides the lowest resistance to movement.