Wk 5 - Linear Kinetics, work, power and energy Flashcards
Momentum is a….?
quantity of motion
The opposite of momentum is ____
inertia
Will someone with larger mass always overrun the smaller mass person when they collide?
No. They have and advantage but the velocity also affects it.
Can there be a conservation of momentum?
Yes (e.g. the metal ball bouncing demonstration)
Absolute total conservation of energy is when …?
No energy is lost through transfer -> last forever
Impulse = _____ x _____
Impulse = Force x time
The area under a force-time curve is called the ____
impulse
_________ = change in momentum
Impulse
What are the two theoretical types of impact?
1) perfectly elastic
2) perfectly plastic
Perfectly elastic means…
velocities of impact before and after impact are equal -> never loses energy
Perfectly plastic means…
Object doesn’t return to original shape after impact
The coefficient of restitution (-e) is a number reflecting…
The rebound properties of the object
If there is no rebound in an object, the e = ??
e = 0
If there is perfect rebound in an object, the e = ??
e = 1
e = √hb / hd (interpret)
e = √ of velocity before and after hitting the ground
______ is a force applied against a resistance multiplied by the displacement if the resistance in the direction of the force
work
Can you have mechanical work without movement?
No. Even if your using your muscle to push something, if it doesn’t move there was no mechanical work
What is positive mechanical work?
If force is applied in same direction that the object moves (generally concentric mm contraction)
What is negative mechanical work?
If force is applied in the opposite direction that the object moves (generally eccentric mm contraction)
________ is the rate at which a force does work
Power
Power = ______ / _______
P = W / Δt
Power = _______ x _____
P = F x v
The less time you take to lift an object the _____ power will develop
more
________ is the capacity to do work
energy
______ ________ is the ability of a moving object to do work
Kinetic energy
_____ _______ is the energy possessed by a body due to its position above a reference surface
potential energy
As an object starts falling, its KE ______ and PE _____
KE increases, PE decreases
____ ______ is the capacity to do work because of a deformed body returning to its original shape
Strain energy
Strain energy is a type of …
potential energy
Can energy be destroyed or gained?
No. it is only transferred
KE + PE =
constant
The work of a force is equal to the change in ______ that it produces in the object acted on
energy
