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    (Original post by speed1✈️✈️)
    Plant? , do you mean planet

    I got something in the order of 10^33, I used Kepler's 3rd law and radius R2 and time period given in question, converted into seconds.
    God I hope we're both right on this one :O
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    (Original post by Kevinwong)
    And mass of the plant was?
    something BIG

    I got 1.0...x10^33 I can't remember the decimals
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    (Original post by Danny.L)
    God I hope we're both right on this one :O
    SAME, just gota pray that TeacherCol agrees

    Shame we might have to wait till tomorrow though, I would have forgotten my answers
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    (Original post by speed1✈️✈️)
    Plant? , do you mean planet

    I got something in the order of 10^33, I used Kepler's 3rd law and radius R2 and time period given in question, converted into seconds.
    Did the second part of the question say the period of S1 was 3 days? I used Keplar's law with R1 and T1 to get M1 and then used the ratio to get M2 but I think I may have made a mistake . Would I still get 1/2 marks?
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    (Original post by Pyslocke)
    Did the second part of the question say the period of S1 was 3 days? I used Keplar's law with R1 and T1 to get M1 and then used the ratio to get M2 but I think I may have made a mistake . Would I still get 1/2 marks?
    3 days????? How???? I never saw that. I am pretty damn certain it was 4 days. I don't know if you would to be honest
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    (Original post by saal180898)
    something BIG

    I got 1.0...x10^33 I can't remember the decimals
    Yep it was you're right


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    (Original post by speed1✈️✈️)
    3 days????? How???? I never saw that. I am pretty damn certain it was 4 days. I don't know if you would to be honest
    It was 4 days


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    (Original post by Pyslocke)
    Did the second part of the question say the period of S1 was 3 days? I used Keplar's law with R1 and T1 to get M1 and then used the ratio to get M2 but I think I may have made a mistake . Would I still get 1/2 marks?
    Well, they told you the period was equal for both of them, 4 days.
    I've no idea if that is right.
    I just used keplers third law with T^2 = (4Pi^2 * R2^3)/(G*M2)
    That got me 1.73*10^33.
    Was it out of 2 or 3?
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    (Original post by speed1✈️✈️)
    3 days????? How???? I never saw that. I am pretty damn certain it was 4 days. I don't know if you would to be honest
    Oh wait my mistake. It was 4 day
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    (Original post by Danny.L)
    Well, they told you the period was equal for both of them, 4 days.
    I've no idea if that is right.
    I just used keplers third law with T^2 = (4Pi^2 * R2^3)/(G*M2)
    That got me 1.73*10^33.
    Was it out of 2 or 3?
    It was worth 3 marks
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    (Original post by Danny.L)
    Well, they told you the period was equal for both of them, 4 days.
    I've no idea if that is right.
    I just used keplers third law with T^2 = (4Pi^2 * R2^3)/(G*M2)
    That got me 1.73*10^33.
    Was it out of 2 or 3?
    I forgot they had the same period >.<. I think I got 10^31. But how come I don't get the same answer?
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    (Original post by Pyslocke)
    I forgot they had the same period >.<. I think I got 10^31. But how come I don't get the same answer?
    The question clearly stated both stars had the same period
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    (Original post by Pyslocke)
    I forgot they were the same period >.<. I think I got 10^31. But how come I don't get the same answer?
    Yeah a couple people in my class got that too. I've done it like 10 times and I consistently get 10^33, perhaps you mis-entered something on your calculator?
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    (Original post by LibertyMan)
    What were your values for S2 people??? I NEED TO KNOW FUSUFBAKFJKDNDKIDJFJ
    I think it was 1.74x10^33
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    Workings to get the mass of S2 for those wondering.
    Attached Images
     
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    (Original post by Danny.L)
    c?
    because when you use kepler's third law the mass you calculated is the capital M not small m. in this case that will be mass c, the centre of rotation.
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    If I got 7.2x10^12 and 2.4x10^12, do i lose one or two marks? Please answer :9
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    (Original post by TheFarmerLad)
    That means nothing to me do you mean I'll lose M1 and A1 (2 marks) or get M1 and A1 (lose 1 mark)? Have to admit it makes me chuckle, can't wait to see the Hitler video!
    i think both
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    (Original post by speed1✈️✈️)
    Really doesn't deserve one to be honest, wasn't as bad as people saying! There have been MUCH worser exams set by OCR - (cough cough G481 June 2015). This years OCR papers seem to be half descent!
    imo this is worse than g481 june 2015
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    (Original post by saal180898)
    ? I thought it said the the distance between the two stars (R1 + R2) = 4.8x10^12
    I am 100% sure that this person Is correct. I read it very carefully. You were supposed to get that equation shown above and that raito, what was it 3R1=R2 or something, then solve simultaneously. it came out with R1=1.2x10^12 and R2=3.6x10^12.
 
 
 
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