Wk 5 - Linear Kinetics, work, power and energy

Question 1

Momentum is a….?

Answer 1

quantity of motion

Question 2

The opposite of momentum is ____

Answer 2

inertia

Question 3

Will someone with larger mass always overrun the smaller mass person when they collide?

Answer 3

No. They have and advantage but the velocity also affects it.

Question 4

Can there be a conservation of momentum?

Answer 4

Yes (e.g. the metal ball bouncing demonstration)

Question 5

Absolute total conservation of energy is when …?

Answer 5

No energy is lost through transfer -> last forever

Question 6

Impulse = _____ x _____

Answer 6

Impulse = Force x time

Question 7

The area under a force-time curve is called the ____

Answer 7

impulse

Question 8

_________ = change in momentum

Answer 8

Impulse

Question 9

What are the two theoretical types of impact?

Answer 9

1) perfectly elastic

2) perfectly plastic

Question 10

Perfectly elastic means…

Answer 10

velocities of impact before and after impact are equal -> never loses energy

Question 11

Perfectly plastic means…

Answer 11

Object doesn’t return to original shape after impact

Question 12

The coefficient of restitution (-e) is a number reflecting…

Answer 12

The rebound properties of the object

Question 13

If there is no rebound in an object, the e = ??

Answer 13

e = 0

Question 14

If there is perfect rebound in an object, the e = ??

Answer 14

e = 1

Question 15

e = √hb / hd (interpret)

Answer 15

e = √ of velocity before and after hitting the ground

Question 16

______ is a force applied against a resistance multiplied by the displacement if the resistance in the direction of the force

Answer 16

work

Question 17

Can you have mechanical work without movement?

Answer 17

No. Even if your using your muscle to push something, if it doesn’t move there was no mechanical work

Question 18

What is positive mechanical work?

Answer 18

If force is applied in same direction that the object moves (generally concentric mm contraction)

Question 19

What is negative mechanical work?

Answer 19

If force is applied in the opposite direction that the object moves (generally eccentric mm contraction)

Question 20

________ is the rate at which a force does work

Answer 20

Power

Question 21

Power = ______ / _______

Answer 21

P = W / Δt

Question 22

Power = _______ x _____

Answer 22

P = F x v

Question 23

The less time you take to lift an object the _____ power will develop

Answer 23

more

Question 24

________ is the capacity to do work

Answer 24

energy

Question 25

______ ________ is the ability of a moving object to do work

Answer 25

Kinetic energy

Question 26

_____ _______ is the energy possessed by a body due to its position above a reference surface

Answer 26

potential energy

Question 27

As an object starts falling, its KE ______ and PE _____

Answer 27

KE increases, PE decreases

Question 28

____ ______ is the capacity to do work because of a deformed body returning to its original shape

Answer 28

Strain energy

Question 29

Strain energy is a type of …

Answer 29

potential energy

Question 30

Can energy be destroyed or gained?

Answer 30

No. it is only transferred

Question 31

KE + PE =

Answer 31

constant

Question 32

The work of a force is equal to the change in ______ that it produces in the object acted on

Answer 32

energy