IT IS THE PRODUCT OF AN OBJECTS MASS AND ITS LINEAR VELOCITY (L(KG M/S) = MASS (KG) X VELOCITY (M/S). THE FASTER AN OBJECT MOVES THE MORE MOMENTUM IT HAS. THE LARGER A MOVING OBJECTS MASS, THE MORE MOMENTUM IT HAS. SO, MOMENTUM IS A WAY OF QUANTIFYING THE MOTION OF INERTIA OF AN OBJECT TOGETHER IN ONE MEASURE. IN ORDER TO CHANGE THE LINEAR MOMENTUM OF AN OBJECT, EITHER ITS MASS OR ITS VELOCITY MUST CHANGE. IN SPORTS, AND HUMAN MOVEMENT, MOST OBJECT WE DEAL WITH HAVE A CONSTANT MASS, AND HENDE, A CHANGE IN MOMENTUM IMPLIES A CHANGE IN VELOCITY. BY THE SAME TOKEN, ANGULAR MOMENTUM QUANTIFIES THE ANGULAR MOTION OF AN OBJECT, AND IS THE PRODUCT OF MASS, HENCE, A CHANGE IN MOMENTUM IMPLIES A CHANGE IN VELOCITY.
THE AVERAGE NET TORQUE (ANGULAR ANALOG OF FORCE) ACTING OVER SOME INTERVAL OF TIME WILL CAUSE A CHANGE IN ANGULAR MOMENTUM OF AN OBJECT (Tat = ∆Ha).
THE TOTAL MOMENTUM OF A SYSTEM OF OBJECTS IS CONSTANT IF THE NET ETERNAL FORCE ACTING ON THE YSTEM IS ZERO. WRITTEN IN ANOTHER WAY, IN ANY SYSTEM WHERE BODIES COLLIDE (AND THERE CAN BE MORE THAN TWO BODIES) OR EXERT A FORCE UPON EACH OTHER, THE TOTAL MOMENTUM IN ANY DIRECTION REMAINS CONSTANT UNLESS SOME EXERNAL FORCE ACTS ON THE SYSTEM IN THAT DIRECTION. THE MOMENTUM POSSESSED BY THE SYSTEM BEFORE THE COLLISION EQUALS THE MOMENTUM POSSESSED BY THE SYSTEM AFTER THE COLLISION (THE AMOUNT OF MOMENTUM IS CONSTANT – IT IS CONSERVED)
THE AVERAGE NET FORCE ACTING OVER SOME INTERVAL OF TIME WILL CAUSE A CHANGE IN LINEAR MOMENTUM OF AN OBJECT (FT = TRIANGLE[L]) WE CAN INTERPRET CJHANGE IN MOMENTUM TO MEAN CHANGE IN VELOCITY, BECAUSE MOST OBJECTS HAVE CONSTATNT MASS
power is the rate of doing work, or how much work is done in a specific amount of time (P (J/s or watts)= W (J)/ ∆t (s)). Power could be thought of as how quickly or slowly work is done. The maximum power producing capacity of humans is related to the duration of the activity involved. A sprinter can produce high powers only for a short period of time, whilst a marathon runner
is the capacity to do work. Mechanical energy comes in two forms: kinetic (KE) and potential (PE) energy. Kinetic energy is due to motion. A moving object has kinetic energy and hence the capacity to do work due to its motion. Potential energy is energy due to position. There are two types of potential energy: gravitational and strain energy. An object has the capacity to do work due to its position relative to the earth (gravitational energy) or deformation (strain energy). Unit of energy is Joules (J).
work done on an object by external forces can cause a change in its energy (W = ∆E). This indicates that production of a large change in kinetic energy (and thus a large change in velocity) requires application of a large force over a long distance. If one wishes to increase the distance an object is thrown, s/he needs to increase work done on the object. By increasing larger muscles to apply larger force on the object and applying the force over a longer distance (e.g. using elbow and wrist rather than wrist only), kinetic energy of the object at release will increase. Subsequently, the object will have larger velocity which results in a longer distance thrown. For a weight which is lifted, increase in the total energy of the weight is due to a change in its position.
is the product of force and amount of displacement in the direction of that force (W (Nm or Joules, J) = Force (N) x displacement (m)). (Mechanical) Work can be positive or negative: positive work is done by a force acting on an object if the object is displaced in the same direction as force. By the same token, work is negative if the force acting on an object is in the opposite direction of the motion (displacement) of the object. When muscles contract, they can do mechanical work. If origin and insertion of muscles get closer to each other, muscles do positive work (concentric contraction). If origin and insertion of muscles get farther from each other (i.e. muscle elongates), muscles do negative work (eccentric contraction). No mechanical work is done during isometric muscle contraction.
is the rate of doing work, or how much work is done in a specific amount of time (P (J/s or watts)= W (J)/ ∆t (s)). Power could be thought of as how quickly or slowly work is done. The maximum power producing capacity of humans is related to the duration of the activity involved. A sprinter can produce high powers only for a short period of time, whilst a marathon runner
The three cardinal planes of movement are sagittal, transverse, and frontal planes. A 2 dimensional (2D) analysis of movement assumes that the movement of interest occur mainly in only one plane (swimming, cycling, running).
Calculating the area underneath velocity-time curve (i.e. integration of velocity-time curve) provides information on the displacement (change in position) taken place. Similarly, integrating acceleration-time curve provides information on the change in velocity.
For example, if a video camera can record 50 frames (still images) of a scene in one second, it has a sampling frequency (rate) of 50 Hz.
refers to the number of times a continuous (analog) signal is sampled (measured) in one second. Unit of sampling frequency is Hertz (Hz).
An external force directed toward the axis of rotation of an object moving in a circular path (McGuinnis, 2013). If an object moves in a circular path, the centripetal force must be acting (Grimshaw et al. 2007). Centripetal force accelerates the object towards the centre of the circular path based on the second Newton’s law of motion (Fcentripetal = m x acentripetal), and this is called centripetal acceleration.
The direction of the net acceleration of the object is determined by the vector sum of tangential (linear) and centripetal accelerations (McGuinnis, 2013).
The object rotating in the circular path has a linear acceleration at any instant of time whose direction is tangential to the circular path (i.e. perpendicular to the centripetal acceleration).
Linear acceleration of a point on a rotating object measured in the direction perpendicular to the circular path of the object (along a line through the axis of rotation (McGuinnis, 2013). The centripetal force causes the object to move in a circle (Grimshaw et al. 2007).
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