Question 2
The power P required
to move an object through a medium at constant speed depends on the speed v and
the resistive force F acting on the object.
The resistive force F also
depends on the speed v.
Which row shows a
possible relationship between speed v, resistive force F and
power P?
resistive
force F power
P
A proportional to v constant
B proportional to v proportional
to v
C proportional to v2 proportional
to v2
D proportional to v2 proportional
to v3
Reference: Past Exam Paper – June 2016 Paper 11 Q17
Solution:
Answer:
D.
We know that
Power = Work done / time =
F × d / t = F × (d/t) = F × v
P = Fv
Now, the resistive force
also depends on speed v. (But we do not know to which ‘power’; e.g. v or v2
or v3 or v4 or … ???)
But, whatever the
relationship between resistive force F and speed v, power P = Fv. So, if
Resistive force F ∝ vn
Power P = Fv and is proportional
to (vn × v =)
vn+1
That is, the exponent of v
for power will be more than that for the force by 1.
Please help me with Q14 march 2017 paper12 tq so much! :)
ReplyDeletesee solution at
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Please help me with these questions ASAP Thanks
ReplyDeleteOct Nov 2015 Paper 11 Questions 19 and 33
May June 2016 Paper 11 Question 10
Oct Nov 2016 Paper 11 Question 13
May June 2018 Questions 9 and 35
Oct Nov 2017 Paper 11 Question 11
Oct Nov 2017 Paper 13 Questions 36 and 37
some of these questions have already been answered.
Deletego through the links at
http://physics-ref.blogspot.com/2018/09/physics-9702-past-exam-paper-worked.html
http://physics-ref.blogspot.com/2014/05/physics-9702-notes-worked-solutions-for.html
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These are the questions I didn't find on the website so then I asked
DeletePlease let me know when and where you have solutions to the above questions
Deletefor november 2017 paper 13, go to
Deletehttp://physics-ref.blogspot.com/2018/11/9702-november-2017-paper-13-worked.html
Why haven't u posted all the solutions. I need 16
ReplyDeleteYou need to work the questions on your own and check for the answers. If you cannot solve specific questions, it is then that you may ask.
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