Questions answered wrong

38問 • 1年前

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A scalar quantity is one that:

is described by a magnitude only

With respect to conducting a video analysis of an athlete, the minimisation of prespective and parralax errors can be best achieved by:

keeping the camera as far from the athlete as practical and zooming in on them

When clearing the bar in a high jump or pole vault competition:

a successful bar clearance may not require the centre of mass to be higher than the bar

The moment of inertia is influenced by what variables?

mass and the distance of the mass from the centre of rotation

The fact that the total angular momentum of a body must retain constant unless an external force (i.e. not an internal one) acts on it is best descibed by which law?

law of conservation of momentum

If a figure skater is doing a pirouette is able to hold their arms closer to their body, such that their moment of inertia is reduced by 10%, what will happen to their angular velocity?

it will increase by 10%

A hurdler is about to clear a hurdle in a race. They therefore lift their lead leg (i.e. lift their front foot) over the hurdle. According to the law of conservation of momentum, in which direction is their upper body likely to rotatate?

forwards, in the opposite direction to the leg being lifted

By what amount does kinetic energy of an object chang as if its velocity triples?

it increases by 9 times

Would you consider momentum (m x v) a vector quantity or scalar quantity?

vector because velocity is a vector quantity, so momentum must have a direction

According to the law of conservation of momentum, in an idal collision:

the product of mass and velocity of all objects is the same before and after the collision

One way to increase the coefficient of restitution in a direct collision is to:

decrease the speed of the objects

A home run is more likely to be hit over right field in basball because:

the greater angle of incidence in the bat-ball collision increases the coefficient of restitution

When measured on a force platform, the coefficient of restitution of friction of an object-platform interface is equal to:

the ratio to the horizontal force to the vertical (normal) force

The wave that forms at the head of a swimmer is commoly called the:

bow wave

One benefit of the small-aplitude flutter kick, which is used by crawl-stroke swimmers, is that:

increases turbulence and thus minimises stern wave formation

Wave drag is:

all the above

Surface drag is strongly influenced by:

all of the above

Form drag is influenced by three parameters, which are the objects:

form drag coefficient (Cpd), frontal surface area and the squared relative velocity (object vs fluid)

Lift forces around an aerofoil (such as the hand in swimming) can be best explained by which of the following mechanisms:

the angle of the aerofoil (or hand) causes a turning of the oncoming fluid and change in fluid direction must occur with an opposite movement of the aerofoil, according to Newton's Second Law (i.e. action-reaction or conservation of momentum)

The lift force about a spining object can be best explained by:

the Magnus Effect

A movement pattern that is ideal for tasks requiring very high forces is the:

push-like pattern

To walk at a constan velocity, energy lost or dissapated through foot-ground collision or dissapated from muscles is replaced:

by active muscle work

In walking, the last phase in which the body is in double support is called?

toe-off or pre-swing

What is an aerofoil?

an object that has a shape that creates lift in a moving fluid

What does "angle of incidence" mean?

the angle between the path of an object and a line drawn perpendicular from the surface with which it is presently in contact (i.e. the normal line)

What does "braking Impulse" mean?

the product if the applied force and the time overwatch it is applied acting to slow an object (often occurs at foot striking in running)

What does "kinetic chain" mean?

the linked segments of a body that move together

What does "moment arm" mean?

the perpendicular distance between a centre of rotation of an object and the line of action of a force acting on the object

What does "Impulse" mean?

the product of applied force and the time over which it is applied

What does "moment" mean?

pertaining to an action at a distance, for example, moment of inertia, moment of force

What does "moment of inertia" mean?

tendency for a rotating body to remain in its present state of motion; equal to the product of the mass of an object and its radius of gyration

What does "perspective error" mean?

the error of size or distance (and its time derivatives) associated with an objects distance from the eyes or camera

What does "realative velocity" mean?

the difference in velocities of two objects or media (for example, object and fluid)

What does "translation" mean?

linear motion

What does "wave" mean?

a drag retarding resistance caused by pressure differences around an object moving at an interface between two liquids (for example, air and water) that results in wave formation in the more dense fluid

What does "work-energy relationship" mean?

the change in energy of a body or system is directly proportional to the work done on the object or system; both work and energy have the same unit of measurement

What does "H or L" mean?

angular momentum

What does "J" mean?

impulse

The Skeletal System

Elmaz Okicic · 11問 · 2年前

The Skeletal System