TORQUE AND CENTER OF GRAVITY Flashcards
An external force directed through the center of gravity of an object is called
centric force
The effect of a centric force is to cause a change in
linear motion
An external force not directed through the center of gravity of an object is called an
eccentric force
The effect of an eccentric force is to cause a change in the
linear and angular motion
what is a force couple
A pair of forces equal in size but opposite in direction and noncolinear
what is a force couple
A pair of forces equal in size but opposite in direction and noncolinear
The effect of a force couple is to cause a change only in
angular motion
why there’s is no change in linear motion with a force couple
The resultant of the two forces in a force couple is a force of zero, so according to Newton’s first and second laws, no change in linear motion occurs
. The torque produced by the force couple causes the object to
rotate
torque is directly related to the _ of the force that creates it
size and the distance between the line of action of the force and the point about which the object tend to rotate
does tThe torque produced by a force depend on the force alone
no
A torque that causes counterclockwise rotation is
positive
A torque that causes clockwise rotation is
negative
A torque that causes clockwise rotation is
negative
A net force of zero ensures that no change will occur in the _ motion of an object, but it does not constrain the object’s _ motion.
linear, angular
what do we need to have if we want to have no angular motion
The net torque acting on an object must be zero to ensure that no changes occur in the angular motion of the object
For an object to be in static equilibrium, the external forces must sum to _ and the external torques (about any axis) must sum to _ as well.
0
what is the def center of gravity
Center of gravity is the point in a body or system around which its mass or weight is evenly distributed or balanced and through which the force of gravity acts
what happen with the center of gravity if you raise your arm in front of you
it will move forward slightly
what happen with the center of gravity you reach overhead with both arms,
it will move upward slightly
Someone with long legs and muscular arms and chest has a _ center of gravity than someone with shorter, stockier legs
Someone with long legs and muscular arms and chest has a higher center of gravity than someone with shorter, stockier legs
women center of gravity is _ compare to men and why
. A woman’s center of gravity is slightly lower than a man’s because women have larger pelvic girdles and narrower shoulders relative to men.
Raising one leg out in front of you will move your center of gravity _ and _ farther than will raising one arm out in front of you
upward and forward
