Flashcards
Physics- Gravitational Fields
Flashcards do conjunto (44)
- 1What will experience an attractive force when placed in a gravitational field?Any object with mass
- 2What will an increase in mass have on the gravitational force?The force will also increase
- 3What objects have a significant gravitational effect here on earth?The moon and the sun- They cause our tides
- 4What do gravitational field lines show?The direction of the force that masses would feel in a gravitational field
- 5If you put a small mass anywhere in the Earths gravitational field where would it be attracted to?The earth
- 6What type of gravitational field is the earth?Far away: Radial
Close to the earths surface: Uniform - 7If you move a mass further away from the earth what effect will this have on the force it experiences?It will decrease
- 8The force experienced by an object in a gravitational field is always ...Attractive and a vector quantity
- 9What do vector quantities depend on?The masses involved and the distances between them
- 10What does Newtons Law of gravitation calculate?The force experienced between two masses
- 11What type of law is the Newtons law of gravitation?An inverse law
- 12In Newtons law of gravitation, if the distance between the masses increases then the force will ...decrease
- 13In Newtons law of gravitation, if the distance doubles then the force will ...be one quarter the strength of the original force
- 14What is field strength defined as?The force per unit of mass
- 15What does the gravitational field strength depend on?Where you are in the field
- 16What are the units for Gravitational field strength?Nkg^-1
- 17What type of quantity is 'g' Gravitational field strength?Vector- always pointing towards the centre of the mass
- 18What can we assume 'g' is at the earths surface?a constant called acceleration due to gravity because the field is uniform
- 19What type of field do point masses have?Radial
- 20In a radial field g is ...inversely proportional to r^2
- 21What does a graph of g against r for the earth look like?
- 22What does the area under a 'g' against 'r' graph find?The gravitational potential
- 23What is gravitational potential defined as?Potential energy per unit mass
- 24What are the units for gravitational potential ?Jkg^-1
- 25Is gravitational potential positive or negative on the surface of the mass?Negative and increases with distance
- 26What will the gravitational potential be at an infinite distance from the mass?Zero
- 27How would a graph look for Gravitational potential varying with distance?
- 28What does the gradient find of a Gravitational potential against distance graph?The value of g at that point
- 29What is gravitational potential difference?The energy needed to move a unit of mass
- 30How are planets and orbits kept in orbit?By the gravitational forces
- 31What keeps any object that is undergoing circular motion in its path?A centripetal force
- 32What does the force depend on? Give an example of this?It depends on the object
In satellites its the gravitational attraction of the mass there orbiting - 33What must the gravitational and centripetal forces equal?Each other
- 34What is the time taken for a satellite to make one orbit called?The orbital period
- 35The greater the radius of a satellites orbit ...The slower it will travel and the longer it will take to complete one orbit
- 36The energy of an orbiting satellite ...Is constant
- 37What energies does an orbiting satellite have?Kinetic and potential energy
- 38In a circular orbit a satellites speed and distance are ...constant; so the kinetic energy and potential energy are also constant
- 39In an elliptical orbit when will a satellite speed up?When its height decreases
- 40In an elliptical orbit when the kinetic energy increases...The potential energy decreases
- 41What do geosynchronous satellites do?orbit directly over the equator and are always above the same point on the earth
- 42What speed does a geosynchronous satellite travel at?the same angular speed as the earth below
- 43What are geosynchronous satellites useful for and why?Sending TV and telephone signals- the satellite is stationary, so don't need to move the angle of your receiver
- 44How long is a geosynchronous orbit?Exactly one day
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- Physics Unit 4 FlashCards sobre Physics- Gravitational Fields, criado por sammy414 em 26-11-2013.
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