final exam

Question 1

coplanar

Answer 1

any system of forces acting in a single plane

Question 2

Concurrent

Answer 2

any system of forces acting at a single point

Question 3

inertia

Answer 3

resistance to motion, directly related to the mass of the object

Question 4

impact peak

Answer 4

impact on the body in landing

Question 5

Joint reaction force

Answer 5

net force acting across the joint

Question 6

friction

Answer 6

a force that acts parellel to the interface of two surfaces

Question 7

centripetal force

Answer 7

act toward the center of rotation when an object moves along a curved path

Question 8

pressure

Answer 8

used to describe force distribution

Question 9

center of pressure

Answer 9

a displacement measure indicating the path of the resultant GRF vector on the force platform

Question 10

passive peak

Answer 10

a phase that is not considered to be under muscular control and is influenced by impact velocity

Question 11

active peak

Answer 11

second peak in GRF, role of muscles play in the force development

Question 12

Law of inertia

Answer 12

every body continues in its state of rest until it is acted upon by an external force

Question 13

Law of acceleration

Answer 13

the rate of change of momentum of a body is proportional to the force causing it, and the change takes place in the direction of the force

Question 14

Law of action-reaction

Answer 14

for every action there is an equal and opposite reaction

Question 15

Torque (Moment of Force)

Answer 15

a force that causes a rotation, the product of a force and the perpendicular distance to its line of action

Question 16

Torque arm (Moment Arm)

Answer 16

The distance r is referred to as the

Question 17

eccentric force

Answer 17

when the force is not applied through the pivot point. literally an off center force

Question 18

force couple

Answer 18

two torques that produce a rotation about their longitudinal axis (backward force with one foot and a forward force with the other foot) F*D=force couple

Question 19

Moment of inertia

Answer 19

dependent not only on the mass of the object but also on the distribution of mass with respect to an axis of rotation

Question 20

Radius of Gyration

Answer 20

denotes the segments mass distribution about the axis of rotation and is the distance from the axis of rotation to a point at which the mass can be assumed to be concentrated without changing the inertial characteristics

Question 21

Parallel Axis Theorem

Answer 21

the moment of inertia can be calculated about any parallel axis, given the moment of inertia about one axis, the mass of the segment, and the perpendicular distance between the parallel axis.

Question 22

Angular momentum

Answer 22

is the quantity of angular motion of an object and has units of Kg-m2.s-1

Question 23

Angular impulse

Answer 23

T x dt

Question 24

conservation of angular momentum

Answer 24

when gravity is the only external force acting on an object, as in projectile motion, the angular momentum generated at takeoff remains constant for the duration of the flight

Question 25

local angular momentum

Answer 25

the angular momentum of a segment about its own center of mass is referred to as

Question 26

remote angular momentum

Answer 26

the angular momentum of a segment about total body center of mass is referred to as

Question 27

center of gravity

Answer 27

the body weight vector originates at a point referred to as

Question 28

center of mass

Answer 28

the point about which the body’s mass is evenly distributed

Question 29

segmental method

Answer 29

involves knowledge of the masses and the location of the centers of mass of each of the body’s segments

Question 30

lever

Answer 30

a rigid rod that is rotated about a fixed point or axis called the fulcrum

Question 31

a lever consists of

Answer 31

a resistance force, an effort force, a barlike structure, and a fulcrum

Question 32

two moment or lever arms are designated as

Answer 32

the effort arm and the resistance arm