ENERGY WORK POWER Flashcards

1
Q

energy

A

the ability to do work

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2
Q

energy is a scalar or vector

A

scalar

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3
Q

translational kinetic energy

A

capacity to do work by virtue of a body’s linear motion

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4
Q

rotational kinetic energy

A

capacity to do work by virtue of a body’s rotational motion

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5
Q

gravitational potential energy

A

capacity to do work by virtue of a body’s position

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6
Q

describe gravity in gravitational potential energy formula

A

gravity will be input as positive because you can’t have negative energy

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7
Q

can you have negative energy

A

NO

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8
Q

strain/spring potential energy

A

capacity to do work by virtue of a deformed body returning to its original shape

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9
Q

what is k in the strain/spring potential energy formula

A

spring constant
-the stiffness of the spring

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10
Q

describe example of strain/spring potential energy

A

an eccentric movement like a golf swing that stretches the tissues (stores potential energy in the tissue itself)
-benefit from the concentric of the movement

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11
Q

heat energy

A

energy lost is dissipated as heat
-micro-movement of particles

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12
Q

work

A

change in mechanical energy

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13
Q

mechanical energy

A

kinetic + potential energy

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14
Q

if movement is in the opposite direction as the force applied then work will be positive/negative
-what type of movement
-what occurs
-name an example of this for a push up

A

negative
-eccentric movement
-attempting to decelerate the body absorbing kinetic energy
-down phase of push up

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15
Q

if movement is in the same direction as the force applied then work will be positive/negative
-what type of movement
-what occurs
-name an example of this for a push up

A

positive
-concentric movement
-attempting to accelerate the body generating kinetic energy
-up phase of push up

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16
Q

if no movement occurs, with applied force, describe mechanical work
-what type of movement
-name an example of this in exercise

A

mechanical work = 0
-isometric movement
-isometric plank

17
Q

ergometry

A

quantifying work performed by the body
-change in energy

18
Q

conservative force

A

a force where work done by that force in moving an object from starting point A to end point B is independent of the path the object takes

19
Q

example of a conservative force

A

gravity
-work done by gravity is not path dependent

20
Q

name a non-conservative force

21
Q

does conservative force mean positive work

A

NO
-just because a force has done negative work doesn’t mean that the force was not a conservative force
-spring forces + gravitational forces store potential energy as they perform negative work on an object

22
Q

conservation of mechanical energy

A

when all forces acting on a body are conservative the body’s total mechanical energy remains constant (projectile motion)

23
Q

can COM be outside physical body

24
Q

Fosbury flop

A

passing body over bar causes COM to pass under bar

25
ergometer
work-measuring device -measures torque over a certain displacement
26
point mass method
work as a change in total energy of the COM -estimate a body as behaving as just a single COM + quantify changes in energy by changes in the gravitational + translational kinetic energy of the body
27
what doesn't the point mass method account for
rotational kinetic energy
28
what is point mass method termed
zero work paradox
29
zero work paradox (for point mass method)
even though you may be putting a lot of effort into a movement, depending on what that movement is, it may not show up in the point mass method -EX: walking -1 cycle of walking- heel strike on right side through gait cycle back to heel strike on right side -point pass method would estimate 0 work done; limited for calculating work of a body when you get back to the same point
30
what does mechanical efficiency in biomechanics take into account
physiological cost -uses gas exchange to figure out metabolic cost for things like a walk
31
power
the rate at which work is performed -rate of energy generation or dissipation
32
what is the integral of power (area underneath the power curve)
work
33
work is the are under what curve
joint power curve
34
above 0 on joint power curve = ?
positive work -concentric muscle conctraction
35
below 0 on joint power curve = ?
negative work -eccentric muscle contraction