chapter 8 - Physics

tangential speed

the linear speed tangent to a curved path, such as in circular motion

rotational speed

the number of orations or revolutions per unit of time; often measured in rotations or revolutions per second or per minute. (scientists usually measure it in radians per second)

rotational inertia

that property of an object that measures its resistance to any change in its state of rotation: if at rest, the body tends to remain at rest; if rotating, it tends to remain rotating and will continue to do so unless acted upon by a external net torque

torque

the product of force and lever arm distance, which tends to produce rotation

torque = lever arm x force

torque equation

center of mass

the average position of the mass of an object. The ____ moves as if all the external forces acted at this point

center of gravity

the average position of weight or the single point associated with an object where the force of gravity can be considered to act

equilibrium

the state of an object in which it is not acted upon by a net force or a net torque

centripetal force

a force directed toward a fixed point usually the cause of circular motion

f = mv^2/r

centripetal force equation

centrifugal force

an outward force apparent in a rotating frame of reference. It is apparent in the sense that it is not part of an interaction but is a result of rotation -- with no reaction-force counter part

angular momentum

the product of a body's rotational inertia and rotational velocity about a particular axis. For an object that is small compared with the radial distance, it can be expressed as the product of mass, speed, and the radial distance of rotation

conservation of angular momentum

when no external torque acts on an object or a system of objects, no change of _____________ can occur. Hence, the ________ before an event involving only internal torques or no torques is equal to the angular momentum after the event.