香港! Member Joined Aug 24, 2005 Messages 467 Location asdasdas Gender Undisclosed HSC 2010 Oct 23, 2005 #21 Napoleon said: your the beast =P not me, thanks for doing on is it easy for you? mind helping me with a few more? Click to expand... Just post all the questions you need help w\... I'm sure all those beasts and monsters out there will help you
Napoleon said: your the beast =P not me, thanks for doing on is it easy for you? mind helping me with a few more? Click to expand... Just post all the questions you need help w\... I'm sure all those beasts and monsters out there will help you
KFunk Psychic refugee Joined Sep 19, 2004 Messages 3,323 Location Sydney Gender Male HSC 2005 Oct 23, 2005 #22 When 0 < θ < 90° then sinθ < tanθ Hence √(rgsinθ ) <√(rgtanθ ), that is, it doesn't have enough speed so it will start to slip down to slope, hence friction will be up the slope.
When 0 < θ < 90° then sinθ < tanθ Hence √(rgsinθ ) <√(rgtanθ ), that is, it doesn't have enough speed so it will start to slip down to slope, hence friction will be up the slope.
Dumsum has a large Member; Joined Aug 16, 2004 Messages 1,552 Location Maroubra South Gender Male HSC 2005 Oct 23, 2005 #23 nevermind.
KFunk Psychic refugee Joined Sep 19, 2004 Messages 3,323 Location Sydney Gender Male HSC 2005 Oct 23, 2005 #24 For part ii) ∑ vertical forces = 0 hence -------> Ncosθ + Fsinθ = mg (1) ∑ horizontal forces = mv<sup>2</sup>/r -----> Nsinθ - Fcosθ = mv<sup>2</sup>/r (2) sinθ x (1) - cosθ x (2) yeilds: F(sin<sup>2</sup>θ + cos<sup>2</sup>θ ) = mgsinθ - mv<sup>2</sup>cosθ/r subbing in the value of v F = mgsinθ - mgsinθcosθ = mgsinθ(1 - cosθ ) up the hill
For part ii) ∑ vertical forces = 0 hence -------> Ncosθ + Fsinθ = mg (1) ∑ horizontal forces = mv<sup>2</sup>/r -----> Nsinθ - Fcosθ = mv<sup>2</sup>/r (2) sinθ x (1) - cosθ x (2) yeilds: F(sin<sup>2</sup>θ + cos<sup>2</sup>θ ) = mgsinθ - mv<sup>2</sup>cosθ/r subbing in the value of v F = mgsinθ - mgsinθcosθ = mgsinθ(1 - cosθ ) up the hill
Dumsum has a large Member; Joined Aug 16, 2004 Messages 1,552 Location Maroubra South Gender Male HSC 2005 Oct 23, 2005 #25 I pretty much had it until I read KFunk's post which proved me wrong (had wrong friction direction) The trick though is in the line (1) x sin@ - (2) x cos@
I pretty much had it until I read KFunk's post which proved me wrong (had wrong friction direction) The trick though is in the line (1) x sin@ - (2) x cos@
N Napoleon New Member Joined Apr 10, 2005 Messages 24 Gender Male HSC 2005 Oct 23, 2005 #26 how you know F is down the slope, not up?