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Geography > Science Study Guide > Flashcards

Science Study Guide Flashcards

1
Q

Machines decrease the amount of energy that is needed to do work

A

True, cause apply less force

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2
Q

Because of friction, using machines increase the amount of energy needed to do work

A

True, cause of friction

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3
Q

An arrangement of multiple pulleys cause the direction of the output force to be opposite to the direction of the input force.

A

True, cause input force is opposite of output force

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4
Q

A first class lever can have a input force greater than the output force

A

When you lift on handle, you don’t need a lot of work

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5
Q

If a person tries to lift a heavy box for 5 seconds and can’t make it budge, the work done on the box is less than zero

A

False, cause it equals zero

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6
Q

A second class lever always has an input force that is less than the output force

A

True, when you lift on the handle you don’t need a lot of force

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7
Q

Increasing the angle a ramp makes with the horizontal decreases the mechanical advantage

A

True, mechanical advantage is equal to length divided by height

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8
Q

A meteorologist trying to predict global warming would consider earth to be a closed system.

A

False, open because there is an exchange of energy and matter

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9
Q

A ball falling under the force of gravity is a closed system.

A

True, no matter is exchanged

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10
Q

Increasing the length of a ramp increases the efficiency of the ramp.

A

True, longer the ramp, less force needed.

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11
Q

A quantity that measures the rate at which work is done is called what?

A

Joules

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12
Q

A quantity that measures how much a machine multiplies force or distance is called what?

A

Work

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13
Q

Power is calculated by dividing work by what?

A

Time

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14
Q

Horsepower is the common unit of power in rating engines. However, the official SI unit of power is the what?

A

Watt

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15
Q

All lovers have a rigid arm that turns around a point called the

A

Fulcrum

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16
Q

A —— is defined as a machine made up of more than one simple machine.

A

Compound machine

17
Q

A —— is an inclined plane wrapped around a cylinder.

A

Screw

18
Q

The ability to do work defines ——

A

Energy

19
Q

The formula for calculating kinetic Energy can be written as ——-

A

KE= 1/2 • m • v 2

20
Q

The stored energy resulting from the relative positions of objects in the system is called ——

A

Potential energy

21
Q

The energy of a moving object due to its motion is called ——

A

Kinetic energy

22
Q

The sum of the kinetic energy and potential energy of large-scale objects in a system is called ——-

A

Mechanical energy

23
Q

Energy that lies at the level of atoms and does not affect motion on a large scale is sometimes called ——

A

Non-mechanical energy

24
Q

The source of the energy when dynamite explodes is ——-

A

Chemical energy

25
Q

The process that transforms light energy into chemical energy in plants is called ——-

A

Photosynthesis

26
Q

The source of the energy is —–

A

Nuclear fusion

27
Q

When a system exchanges energy with the environment outside the system, it is called a ——-

A

Open system

28
Q

A ——- exchanges energy with the outside.

A

Closed

29
Q

The ratio of useful work output to work input is a measure of ——-

A

Mechanical advantage

30
Q

Energy is transferred as ——- when mechanical energy decreases and temperature increases

A

Friction

31
Q

Three children exhaust himself trying to push a large rock that doesn’t budge. Have they done any work? Why?

A

No, because the object must move

32
Q

Do machines reduce the amount of work we have to do? If not, why are machines so useful?

A

No, they only reduce the amount of input force needed to do the job.

33
Q

How does a pendulum show the relationship between gravitational potential energy and kinetic energy?

A

Because of the gravitational pull on the objects a pendulum swings down then the acceleration brings it up then potential energy brings it back down.

34
Q

What is nuclear fusion?

A

A kind of reaction in which right atomic nuclear combine to form a heavier nucleus

35
Q

Why is light considered a form of energy?

A

Because light travels across empty space in the form of electromagnetic waves

36
Q

What is the law of conservation of energy?

A

Energy cannot be created or destroyed, only transferred.

37
Q

What is the difference between an open system and a closed system?

A

In the open system matter and energy are exchanged. In the closed system if energy is exchanged, matter is not

38
Q

What is meant by the efficiency of a machine?

A

The efficiency of the machine is a measure of how much useful work a machine can do. Efficiency equals useful work output divided by work input.

39
Q

Where does energy go when it seems to disappear?

A

It does not disappear, just changes form

Geography (9 decks)

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