12: The Gravitational Field Flashcards

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1
Q

What is angular velocity?

A

The angle the object rotates through per second

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2
Q

Why is a car travelling at constant speed in a circle, accelerating?

A

It’s velocity is changing since its direction is changing

And acceleration = rate of change of velocity

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3
Q

In which direction is a car travelling in a circle, accelerating?

A

Centripetal acceleration is always directed towards the centre of the circle

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4
Q

What produces the centripetal acceleration?

A

Centripetal force

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5
Q

In which direction does centripetal force act?

A

Towards the centre of the circle

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6
Q

What is a gravitational field?

A

A region where an object will experience a non-contact force

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7
Q

What does an object experience when you put it in a gravitational field of another object?

A

Experience an attractive force

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8
Q

What are gravitational field lines?

A

Arrows showing the direction of the force that masses would feel in a gravitational field

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9
Q

What is a uniform field? How can you identify a uniform field with field lines?

A

A field that is the same everywhere. This is shown by the field line being equally spaced and going in the same direction

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10
Q

Point masses have a [ ] field

Point masses = ….

A

Radial

A mass where its assumed they act as if all there mass in concentrated at their centre

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11
Q

As a mass gets further from earth, what happens to the strength of the force it experiences? How is that represented in field lines?

A

Further - force decreases

Lines of force are further apart

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12
Q

Why does a small mass in earth’s gravitational field not affect earth much?

A

Earth is so much more massive

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13
Q

What can you assume about the gravitational field at the surface of Earth? How is this represented in field lines?

A

Assume it is perfectly uniform

So the field lines are parallel and equally spaced

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14
Q

The force experienced by an object in a gravitational field is always [ ]

A

Attractive

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15
Q

What is gravitational field strength?

A

Force per unit mass

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16
Q

A mass in a uniform gravitational field experiences a [ ] force

A

constant - because g will be the same everywhere

17
Q

When is ΔEɢᵣₐᵥ positive? Negative?

A

Positive: When the height increases
Neg: When the height decreases

18
Q

What is the principle of conservation of energy?

A

Energy cannot be created or destroyed. Energy can be transferred from one form to another but the total amount of energy in a closed system will not change

19
Q

You [ ] gravitational potential energy if you move away from the Earth

A

Gain

20
Q

Egrav is always positive/negative

A

Negative (always attractive)

21
Q

Egrav = Δs * [ ]

A

F grav

22
Q

What is gravitational potential?

A

Potential energy per unit mass

23
Q

What do equipotentials show?

A

All the point in a field which have the same potential

24
Q

If you travel along a line of equipotential you don’t lose or gain [ ]

A

Energy - no work is done

25
Q

What shape are the equipotentials around a uniform spherical mass?

A

Spherical surfaces

26
Q

Equipotentials and field lines are parallel/perpendicular

A

Perpendicular

27
Q

What is a satellite?

A

A small mass that orbits a much larger mass

28
Q

When something is in orbit, which 2 forces must be equal?

A

Centripetal force and gravitational force

mv²/r = GmM/r²