Module 5 - 5.4.4 Gravitational Potential and Energy

Question 1

Gravitational Potential, Vg (definition)

Answer 1

The gravitational potential at a point in a gravitational field is the energy required per unit mass to move an object from infinity to that point in the field

Question 2

At infinity, Vg is equal to

Answer 2

0

Question 3

The work done on a body in bringing it to any point in the gravitational field will be – since …

Answer 3

• negative
• since the objects is attracted to the mass that created the field

Question 4

Gravitational Potential Energy (definition)

Answer 4

The work done in bringing an object from infinity to a point in the gravitational field

Question 5

The closer to the body, the — the gravitational potential energy

Answer 5

more negative

Question 6

Escape Velocity (definition)

Answer 6

The escape velocity from a point in a gravitational field is the minimum launch velocity required to move an object from that point to infinity

Question 7

If an object is thrown up in the air on Earth (2)

Answer 7

• its velocity will start to decrease from the instant it is projected upwards
• since the Earth’s gravitational field causes it to be attracted back to Earth

Question 8

Planets closer to the Sun are (2)

Answer 8

• hotter
• so their gases move faster

Question 9

Escape Velocity formula

Answer 9

1/2 mv^2 >/ GMm/r