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Kinetic Energy vs time graph of free falling object? watch

1. Attachment 541399541401
The image says it all basically.
I'm contemplating between A and B but i'm unsure as to which is the correct one and why
Thanks
Attached Images

2. Kinetic energy is 0.5*mass*(velocity)^2. If you know the object is in free fall then you know the only force acting on it is g and a resistive force so you can work out how v evolves with time and hence kinetic energy.

Massive hint: the object reaches terminal velocity, so the kinetic energy must tend to a constant value: only one of those graphs goes to a constant kinetic energy...
3. (Original post by ksrw395)
Attachment 541399541401
The image says it all basically.
I'm contemplating between A and B but i'm unsure as to which is the correct one and why
Thanks
The closer and closer the body gets to its terminal velocity, the lower the rate of change of kinetic energy. In A, rate of change is constant, so...
4. I'm pretty sure it's C as kinetic energy is proportional to velocity squared (KE=0.5mv^2) and velocity is increasing due to the objects weight
5. (Original post by ryn_ptrs)
I'm pretty sure it's C as kinetic energy is proportional to velocity squared (KE=0.5mv^2) and velocity is increasing due to the objects weight
C gives the impression that the kinetic energy is tending to infinity i.e. the object is getting faster and faster and faster rather than its speed levelling off
6. (Original post by Serpentine111)
Kinetic energy is 0.5*mass*(velocity)^2. If you know the object is in free fall then you know the only force acting on it is g and a resistive force so you can work out how v evolves with time and hence kinetic energy.

Massive hint: the object reaches terminal velocity, so the kinetic energy must tend to a constant value: only one of those graphs goes to a constant kinetic energy...
So in other words...B since it tends to level off
7. Where did you get this question? SAT? :O
8. (Original post by Student403)
Where did you get this question? SAT? :O
Cape Unit 1
Paper 1
2014
9. (Original post by ksrw395)
So in other words...B since it tends to level off
Yep
10. (Original post by Serpentine111)
Yep
Nice Thank you
11. (Original post by 13 1 20 8 42)
The closer and closer the body gets to its terminal velocity, the lower the rate of change of kinetic energy. In A, rate of change is constant, so...
Thanks
12. I would say B because as soon as it reaches terminal velocity then Ek will be constant as Ek =1/2MV^2 where mass is constant. A would be the graph if it continually increased but Ek will eventually come to a limit as the terminal velocity occurs when frictional forces balances out with weight of the downwards moving object.
Hopefully I didn't just ramble on and it's the wrong answer haha.

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13. (Original post by RossB1702)
I would say B because as soon as it reaches terminal velocity then Ek will be constant as Ek =1/2MV^2 where mass is constant. A would be the graph if it continually increased but Ek will eventually come to a limit as the terminal velocity occurs when frictional forces balances out with weight of the downwards moving object.
Hopefully I didn't just ramble on and it's the wrong answer haha.

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Thanks haha and no its correct
14. (Original post by ksrw395)
Thanks haha and no its correct
Thanks! May I ask what level you are studying at ? I did Scottish higher physics this year which is similar to A level I think and recently sat the exam for it last week.

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15. (Original post by RossB1702)
Thanks! May I ask what level you are studying at ? I did Scottish higher physics this year which is similar to A level I think and recently sat the exam for it last week.

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Well in my country, Trinidad (in the Caribbean), its just called A level or "form 6" which consists of two units. (each unit is a school year long)
The examinations are called CAPE (Caribbean Advanced Proficiency Examination)
(not sure if this answers your question lol)
16. (Original post by ksrw395)
Well in my country, Trinidad (in the Caribbean), its just called A level or "form 6" which consists of two units. (each unit is a school year long)
The examinations are called CAPE (Caribbean Advanced Proficiency Examination)
(not sure if this answers your question lol)
Ok man cool! Yeah I'm just really curious to see if the things you are doing right now are any what similar to what I'm doing in physics right now. I know a fair deal about types of energy like kinetic energy and potential energy etc.

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17. (Original post by ksrw395)
Thanks haha and no its correct
wait? What's the answer?

I thought its B?
18. (Original post by XxKingSniprxX)
wait? What's the answer?

I thought its B?
It is B, he didn't say it wasn't he was saying no to me thinking B could be wrong. B is the correct answer.

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