Flashcards
gravitational field
Cards in this deck (25)
- 1what is gravitational fieldthe region surrounding an object in which it exerts a gravitional force on any other object.
- 2what is field lines / line of force?whan a small test mass is placed next to a massive body, the massive body pulls/ attracts the small test mass. the path the small test mass follows is called field line.
- 3what is the strength of a gravitational field?it's the force per unit mass on a small test mass placed in the field.
state the formula - 4why is an object that free falls not weightlessbecause its acted on by the force of gravity instead we say its unsupported
- 5what is radial fieldsa field in which the field lines are straight and converge or diverge as if from a single point
- 6when does gravity field get strongwhen the field lines get closer
- 7what is uniform fielda region where the gravitational field strength is the same in magnitude and direction at every point in the field. the field lines are parallel. like a small region on the surface of the earth.
- 8what is the gravitational field strength of the earths surface9.8N kg^-1
- 9does earth have a radial or uninorm fieldit has a radial field
- 10define gravitational potentialat a point is the work done per unit mass to move a small object from infinity to that point.
state the formula - 11what is equipotential?a line or surface in a field along which the electric or gravitational potential is constant.
- 12Newton's law of gravitationevery particle in the universe attracts every other particle with gravitational force that is proportional to the product of the masses and inversely proportional to the square of the distance between them (form their centres).
state the formula - 13Newtons law of gravitation assumes..the force between two point objects is
*always attractive force
*proportional to the product of masses
*inversely proportional to distance apart squared - 14gravitational potential is a scalar or a vector?scalar
- 15formulae for gravitational field strength
- 16formula for gravitational potential
- 17formula for gravitational potential. work done formualwork done = gravitional potential x mass
- 18graph of gravitational field strength vs distance for earth
- 19graph of gravitational potential field strength vs distance for the mooncheck notes
- 20gravitational potential strength vs distance sum of potential energy for moon and earthcheck notes
- 21derive an expression for geostationary satelliteF = m x v^2 / r
F = G x M x m / r^2
m x v^2 /r = G x M x m / r^2
v^2 = G x M / r
because v = circumference of orbit / time
2 pie r / t
(2 pie r)^2 = G x M / r
r^3 / t^2 = G x M / 4 pie^2 - 22properties of geostationary satelliteorbits the earth directly above the equator and has a time period of exactly 24 hours
remains in a fixed position above the equator because it has same time period as the earth's rotation. - 23properties of geosynchronous satelliteorbits over equator
maintains a fixed position relative to surface of earth
period is 24 hours same as earths rotation
steerable dish not necessary.
offers uninterrupted communication between transmitter and receiver. - 24from a planet where is the gravitational energy 0its at infinity. the surface of the planet has negative gravitational potential, it increases to zero (infinity)
- 25what s the total energy when the satellite is in circular orbitits total energy is constant since gpe and kinetic energy are both constant.
kinetic energy increases when its moving towards the earth. gpe increases when its mvng away from the earth.
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- A level Physics (Gravitational field) Flashcards on gravitational field, created by Mohamed Essa on 14/04/2017.
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- Mohamed Essa
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