Gravity: Chapter 6

Question 1

Universal Law of Gravitation

Answer 1

There is a gravitational attraction between any two objects. Masses attract and the force acting on each mass is equal.

Question 2

Inverse-square law

Answer 2

Force is inversely proportional to the square of the distance. The force of attraction drops quickly as two objects move apart.

Question 3

Gravitational field

Answer 3

A collection of vectors, one at each point in space, that determines the magnitude and direction of the gravitational force.

Question 4

Gravitational field strength

Answer 4

The magnitude of the gravitational field vector at a point in space.

Question 5

Satellite

Answer 5

An object or body that revolves around another body due to gravitational attraction.

Question 6

Artificial satellite

Answer 6

An object that has been intentionally placed by humans into orbit around earth or another body; referred to as “artificial” to distinguish from natural satellites such as the moon.

Question 7

Orbital radius

Answer 7

The distance between the venture of the satellite and the centre of its parent body.

Question 8

What is the formula for finding the orbital radius

Answer 8

V = √GM/r2

Question 9

Geosynchronous orbit

Answer 9

The orbit around earth of an object with an orbital speed matching the rate of earths rotation; the period of such an orbit is exactly one earth day. V = 2πr/t.

Question 10

Law of Electric Charges

Answer 10

Like charges repel and unlike charge attract.

Question 11

How do you calculate the total charge of an object?

Answer 11

Calculate the sums of the charges.

Question 12

A deficit of electrons

Answer 12

Means object is positively charged

Question 13

Excess of electrons

Answer 13

Number is negatively charged.

Question 14

Law of conservation of charge

Answer 14

In the transfer of any charge from one object to another, charge can be created or destroyed, but the total charge of a closed system remains constant.

Question 15

Coulomb?

Answer 15

The SI unit for charge.

Question 16

When does electric force become stronger?

Answer 16

As the amount of charge is increased.

Question 17

Electric force

Answer 17

A force with magnitude and direction that acts between two charged particles.

Question 18

Coulomb’s law

Answer 18

The force between two point charges is inversely proportional to the square of the distance between charges and directly proportional to the product of the charges.

Question 19

What is a similarity between Coulomb’s law and universal gravitation?

Answer 19

Both of these laws describe the force between two objects on both depend on certain properties of the object involved. Both laws state that the gravitational force and electric force decrease as the distance between the two interacting objects increases.

Question 20

Electric field

Answer 20

The region in which a force is exerted on an electric charge; the electric force per unit positive charge; unit is N/C. Denoted by E.

Question 21

electric field lines

Answer 21

The continuous lines of force around charges that show the direction of the electric force at all points in the electric field.

Question 22

Electric dipole

Answer 22

A pair of equal and opposite electric charges with centres separated by a small distance. Field lines from -q and +q alone are just field lines going inward and outward, but when they are put farther apart it causes the field lines to bend they interact with each other creating a net electric field.

Question 23

When is the electric field uniform

Answer 23

When the planes of charge extends from the positive plane of charge to the negative plane and is uniform.

Question 24

Is work equal to electric energy?

Answer 24

Yes

Question 25

Electric potential energy

Answer 25

The energy stored in a system of two charges a distance apart, or the energy stored in an electric field that can do work on a positively charged particle. This is work done against the field.

Question 26

Electric potential due to a point charge

Answer 26

The electric potential is inversely proportional to the distance from the charge and proportional to the amount of charge producing the field. If the charge producing the electric field has the same sign as the test charge q, the work done by the electric field on q is negative.