Projectile motion Q (1 Viewer)

[BenBrownTown]

Hey I am trying do Question 7 part (d) from the 1995 paper, Can someone please post up some working please I have managed to get it to isolate V^2 but don't understand what happens to the equality and the inequality.
http://www.boardofstudies.nsw.edu.au/hsc_exams/hsc2000exams/hsc00_maths/95MAT3U.PDF

Thankyou very much

 

[Zenox]

Hey I am trying do Question 7 part (d) from the 1995 paper, Can someone please post up some working please I have managed to get it to isolate V^2 but don't understand what happens to the equality and the inequality.
http://www.boardofstudies.nsw.edu.au/hsc_exams/hsc2000exams/hsc00_maths/95MAT3U.PDF

Thankyou very much

<a href="http://www.codecogs.com/eqnedit.php?latex=Ball~clears~fence~when~y\geq h ~and~x=R \\\\ Thus, ~ h@plus;Rtan\alpha -\frac{R^2g}{2V^2cos^2\alpha } \geq h" target="_blank"><img src="http://latex.codecogs.com/gif.latex?Ball~clears~fence~when~y\geq h ~and~x=R \\\\ Thus, ~ h+Rtan\alpha -\frac{R^2g}{2V^2cos^2\alpha } \geq h" title="Ball~clears~fence~when~y\geq h ~and~x=R \\\\ Thus, ~ h+Rtan\alpha -\frac{R^2g}{2V^2cos^2\alpha } \geq h" /></a>

 

[Zenox]

My apologies, misread q

 

[BenBrownTown]

<a href="http://www.codecogs.com/eqnedit.php?latex=Ball~clears~fence~when~y\geq h ~and~x=R \\\\ Thus, ~ h@plus;Rtan\alpha -\frac{R^2g}{2V^2cos^2\alpha } \geq h" target="_blank"><img src="http://latex.codecogs.com/gif.latex?Ball~clears~fence~when~y\geq h ~and~x=R \\\\ Thus, ~ h+Rtan\alpha -\frac{R^2g}{2V^2cos^2\alpha } \geq h" title="Ball~clears~fence~when~y\geq h ~and~x=R \\\\ Thus, ~ h+Rtan\alpha -\frac{R^2g}{2V^2cos^2\alpha } \geq h" /></a>

you have to substitute v^2 from previous expression as well i just got lost in the algebra and how to determine the inequalities direction

My apologies, misread q

its all good man, no worries, do you know how to get an answer but?

 

[Zenox]

you have to substitute v^2 from previous expression as well i just got lost in the algebra and how to determine the inequalities direction

Post your working

 

[BenBrownTown]

Post your working

sorry for the messy writing
the last three lines I found working for in the sucess book but i just dont understand after you sub in v^2

 

[Zenox]

From c you showed v^2 => ... Now if LHS=...*v^2 , it follows LHS must be =>...*v^2. Sorry im on my phone

 

[unLimitieDx]

Are you asking why you need to sub in v^2?

 

[BenBrownTown]

From c you showed v^2 => ... Now if LHS=...*v^2 , it follows LHS must be =>...*v^2. Sorry im on my phone

All good I figured it out I was making it harder for myself by subbing in V^2 in an awkward position, thankyou for your help

Are you asking why you need to sub in v^2?

no I was trying to figure out what was happening with the inequaility, but i got it, i know why i have to sub in v^2