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AQA A2 physics gravitational fields
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Hey can some one help me to solve this question please.
A satellite X is in a circular orbit of radius r about the centre of a spherical planet of mass M.
Which line, A to D, in the table gives correct expressions for the centripetal acceleration a and the speed v of the satellite?
Answer is
acceleration= GM/r*2 and speed = √GM/r
A satellite X is in a circular orbit of radius r about the centre of a spherical planet of mass M.
Which line, A to D, in the table gives correct expressions for the centripetal acceleration a and the speed v of the satellite?
Answer is
acceleration= GM/r*2 and speed = √GM/r
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#2
so the satellite experiences a gravitational force of GMm/r^2. This is the same as a centripetal force acting on the satellite as the satellite orbits around the planet with circular motion. Hence GMm/r^2 = mv^2/r (centripetal force acting on the satellite). Cancel out the mass of the satellite on both sides (little m) and rearrange to find v.
Centripetal acceleration is given by v^2/r. As you figured out v, you just need to substitute the expression for v you figured out into the equation for centripetal acceleration.
Centripetal acceleration is given by v^2/r. As you figured out v, you just need to substitute the expression for v you figured out into the equation for centripetal acceleration.
Last edited by kursk1896; 1 year ago
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okay got it. Thank you so much 
(Original post by kursk1896)
so the satellite experiences a gravitational force of GMm/r^2. This is the same as a centripetal force acting on the satellite as the satellite orbits around the planet with circular motion. Hence GMm/r^2 = mv^2/r (centripetal force acting on the satellite). Cancel out the mass of the satellite on both sides (little m) and rearrange to find v.
Centripetal acceleration is given by v^2/r. As you figured out v, you just need to substitute the expression for v you figured out into the equation for centripetal acceleration.
so the satellite experiences a gravitational force of GMm/r^2. This is the same as a centripetal force acting on the satellite as the satellite orbits around the planet with circular motion. Hence GMm/r^2 = mv^2/r (centripetal force acting on the satellite). Cancel out the mass of the satellite on both sides (little m) and rearrange to find v.
Centripetal acceleration is given by v^2/r. As you figured out v, you just need to substitute the expression for v you figured out into the equation for centripetal acceleration.
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#4
(Original post by kursk1896)
so the satellite experiences a gravitational force of GMm/r^2. This is the same as a centripetal force acting on the satellite as the satellite orbits around the planet with circular motion. Hence GMm/r^2 = mv^2/r (centripetal force acting on the satellite). Cancel out the mass of the satellite on both sides (little m) and rearrange to find v.
Centripetal acceleration is given by v^2/r. As you figured out v, you just need to substitute the expression for v you figured out into the equation for centripetal acceleration.
so the satellite experiences a gravitational force of GMm/r^2. This is the same as a centripetal force acting on the satellite as the satellite orbits around the planet with circular motion. Hence GMm/r^2 = mv^2/r (centripetal force acting on the satellite). Cancel out the mass of the satellite on both sides (little m) and rearrange to find v.
Centripetal acceleration is given by v^2/r. As you figured out v, you just need to substitute the expression for v you figured out into the equation for centripetal acceleration.
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#5
(Original post by A Smart Guy)
i know this thread is old but where did you get the equation: GMm/r^2 from? I'm doing year 2 a level
i know this thread is old but where did you get the equation: GMm/r^2 from? I'm doing year 2 a level
When I did this question I used the formula sheet g=GM/r^2 for a at the start
then a = v^2 / r which is equal to GMm/r^2. Finally equalling v = square root of (GM/r)
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#6
(Original post by charlottefife)
formula sheet? F= gMm/r^2
When I did this question I used the formula sheet g=GM/r^2 for a at the start
then a = v^2 / r which is equal to GMm/r^2. Finally equalling v = square root of (GM/r)
formula sheet? F= gMm/r^2
When I did this question I used the formula sheet g=GM/r^2 for a at the start
then a = v^2 / r which is equal to GMm/r^2. Finally equalling v = square root of (GM/r)
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#7
(Original post by A Smart Guy)
My teacher gave us this question before we even went over gravitational fields, he probably assumed it only had to do with circular motion
My teacher gave us this question before we even went over gravitational fields, he probably assumed it only had to do with circular motion
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