Kinesiology Chapter 7

equilibrium

state achieved if the resultant force and net torque acting upon an object are equal to zero

linear or translational equilibrium

achieved when the net of the external forces acting upon a system is equal to zero

tug of war when both teams are pulling with equal force

example of a linear equilibrium

rotational torque

achieved when the net of the external torques acting upon a system is equal to zero

a balanced teeter-totter

example of rotational torque

static equilibrium

a situation in which the system is in linear and rotational equilibrium and possesses zero linear or rotational velocity - the object is completely at rest

dynamic equilibrium

a system is in motion, but it is experiencing no change in velocity or direction

riding in an elevator

example of dynamic equilibrium

increase

does the weight of your body increase or decrease as the elevator accelerates upward

decrease

does the weight of your body increase or decrease as the elevator accelerates downward

stability

the resistance of an object to having its equilibrium disturbed

balance

the ability to control the current state of equilibrium, which implies conscious effort and coordination

stable equilibrium

state in which a large force or torque is required to disrupt an object’s current position

unstable equilibrium

a state in which very little force or torque is required to disrupt an object’s current position

neutral equilibrium

state in which an object has no tendency to fall in one direction or the other

linear stability

the resistance of a body to having its linear equilibrium disrupted

mobility

increased stability is often accompanied by decreased

mass

what is one of the major factors that effects linear stability

rotational stability

the resistance of a body to having its rotational or angular equilibrium disrupted

base of support

the entire area bounded by a perimeter formed by the object’s points of contact with a resistive surface that provides a counterforce

directly

rotational stability is _____ related to the location of the center of gravity

keep the center of gravity in the middle of the base of support

what is one way to increase rotational stability

less

the larger the base of support, the ____ likely it will be to experience a loss of stability

the more unstable

the higher the center of gravity,