# Rotational Equilibrium & Dynamics

 torque a quantity that measures the ability of a force to rotate an object around some axisgreater torque means greater ability to rotate an object lever arm the perpendicular distance from the axis of rotation to the line drawn along the direction of the force center of mass the point at which all the mass of the body can be considered to be concentrated when analyzing translational motion moment of inertia the tendency of a body rotating about a fixed axis to resist a change in rotational motion angular momentum the product of a rotating object's moment of inertia and angular speed about the same axis rotational kinetic energy the energy of an object due to its rotational motion t=flθ torque=magnitude of the force x l the distance from the axis of rotation to the force (aka lever arm) x angle btwn force and distance from axis torque SI units Nm positive/negative rotation positive: counter clockwisenegative: clockwise what produces torque only the tangential component of force produces torque; not the radial force equilibrium with rotational motion neither linear nor rotational motion will change all external forces and torques must be zero translational equilibrium sum of net forces is zero; force condition rotational equilibrium sum of net torques must be zero; torque condition extended object object that has a definite, finite size and shape axis of rotation like a line that passes through a hinge that allows things to rotate relationship btwn lever arm and torque farther the force is from the axis of rotation, the easier it is to rotate an object and the more torque is producedsmaller torque=shorter lever arm center of gravity position at which Fg acts on extended object as if it were point mass moment of inertia tendency of a body rotating with a fixed axis to resist a change in rotational motion difference btwn mass and moment of inertia mass is intrinsic, moment of inertia is not relationship between mass distance from axis and moment of inertia farther mass is from axis, greater moment of inertia, greater difficulty to rotate relationship btwn mass and moment of inertia moment of inertia is greater for more massive things second condition for equilibrium complete equilibrium depends on both no net force and no net torque AuthorGymnastxoxo17 ID275452 Card SetRotational Equilibrium & Dynamics Descriptiond Updated2014-05-27T10:21:54Z Show Answers