3.1 Uniform Gravitational Fields Flashcards Preview

A-Level Physics EDEXCEL Year 2 > 3.1 Uniform Gravitational Fields > Flashcards

Flashcards in 3.1 Uniform Gravitational Fields Deck (25)
Loading flashcards...
1
Q

What is a gravitational field?

A

a region where a mass feels a force

2
Q

What kind of a force does a mass feel in this region?

A

A non-contact one

3
Q

Objects of what interact through gravitational field?

A

of a mass

4
Q

What does the gravitational field of the sun do?

A

Keep the planets around it in orbit , by its gravitational ‘pull’

5
Q

Do humans experience a gravitational pull by the earth?

A

Yes, due to the force called weight (as we have mass)

6
Q

Why do object with a greater mass have a more significant effect on gravitational fields?

A

As the force felt/provided depends on the mass

7
Q

Any object with a mass will experience a force of what if put within a force field of another object (gravitational field).

A

of gravitational attraction

8
Q

can gravitational force be both attractive and repulsive?

A

No, only attractive

9
Q

What do we assume about the gravitational field strength near the surface of the earth?

A

We assume it is constant and hence we assume the gravitational field is uniform?

10
Q

What is the gravitational field strength defined as?

A

Gravitational force per unit mass acting on a mass at that point in the field

11
Q

What is the equation for gravitational field strength?

A
g = F / m 
g = gravitational field strength (Nkg^-1 or kgms^-2)
F = gravitational force (N)
m = mass (kg)
12
Q

what is gravitational field strength approx. at earth’s surface?

A

9.81 Nkg^-1

13
Q

is gravitational field strength a vector or a scalar?

A

Vector, it always points towards the centre of mass creating the field

14
Q

Is the gravitational field pointing in the same direction as the force it exerts on objects of mass?

A

Yes

15
Q

What else can gravitational field strength be taken as near earth’s surface?

A

The acceleration, since F = ma

16
Q

What is this acceleration often called?

A

Acceleration due to gravity

17
Q

Is the gravitational field of the earth actually uniform?

A

No, it is radial but along the surface the change in strength is so little that we consider it to be uniform

18
Q

Does the value of gravitational field strength vary around the world?

A

Yes, as the earth is not an exact sphere

19
Q

In terms of gravitational potential what is the magnitude of it at earth’s surface?

A

0, it is said to be an equipotential surface

20
Q

When moving along a equipotential what doesn’t happen?

A

The work isn’t done

21
Q

What is an equipotential

A

Region of equal potential

22
Q

Moving from one equipotential to other causes what?

A

A change in gravitational potential energy (gpe)

23
Q

How do we work out the change in gravitational potential in a uniform field?

A

g x change in distance

it gives units of Jkg^-1

24
Q

Why are the units Jkg^-1

A

as gravitational potential is defined as potential energy per unit mass

25
Q

So to work out the change in GPE what do we need to do to equipotential value?

A

Times it by the mass of the object

Decks in A-Level Physics EDEXCEL Year 2 Class (90):