Exam 4 Flashcards

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1
Q

What’s the formula for work?

A

force x distance

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2
Q

What’s the formula for power?

A

work/time

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3
Q

What’s mechanical energy?

A

when work is done on an object, object acquires ability to do work

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4
Q

What are the 2 types of mechanical energy?

A

potential and kinetic

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5
Q

What is potential energy and what does it depend on?

A

energy of position or configuration; reference point

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6
Q

What’s kinetic energy?

A

energy of motion

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7
Q

What’s total work?

A

work done by all forces acting on mass; change in kinetic energy

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8
Q

Where did the concept of conservation of energy came from?

A

Galileo’s inclines

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9
Q

What’s the condition for conservation of mechanical energy?

A

no work can be done on the object by a nonconservative force

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10
Q

What’s a nonconservative force? What’s an example?

A

a force that converts mechanical energy into another form; friction

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11
Q

What’s the formula for efficiency?

A

work done/energy used

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12
Q

What’s considered the graveyard of useful energy?

A

heat

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13
Q

What’s the formula for energy efficiency ratio(EER)?

A

output capacity/input energy

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14
Q

Can kinetic energy be canceled? Why?

A

no; it’s a scalar

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15
Q

Can momentum be cancelled?

A

yes, when the object’s mass doubles and its traveling half the speed

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16
Q

Explain the law of inertia for rotating systems.

A

an object rotating about an axis tends to remain rotating at the same rate about the same axis unless interfered with by same external influence

17
Q

What is a torque? What does it do?

A

rotational analog of force; changes the rotational state of motion

18
Q

What’s the formula for torque?

A

force x lever arm length

19
Q

True or False. Torque is a vector.

A

true

20
Q

What does it mean by center of mass?

A

average position of mass

21
Q

What does it mean by center of gravity?

A

average position of weight

22
Q

What happens to the path of center of mass of a rotating object if no external forces act on the object?

A

will be a straight line

23
Q

What is the equilibrium if an object is displaced slightly from equilibrium and released, and the object moves to a new position?

A

unstable

24
Q

What is the equilibrium if an object is displaced slightly from equilibrium and released, and the object returns to its old position?

A

stable

25
Q

What is the equilibrium if an object is displaced slightly from equilibrium and released, and the object remains where it is?

A

neutral

26
Q

What is centripetal force?

A

center seeking force

27
Q

What is centrifugal force?

A

center fleeing force

28
Q

True or False. Centrifugal force is a pseudo (fictious) force.

A

true

29
Q

How do you change the angular momentum of an object?

A

an external torque is required

30
Q

What is the formula for gravity?

A

W=mg; g= gravitional force acting on m

31
Q

What happens to force of gravity as the distance increases?

A

decreases

32
Q

Which full moon results in spring tides?

A

full