Yet Another Projectile Motion Question (1 Viewer)

[locked.on]

Having trouble with another problem from the Jacaranda textbook.
Chapter 2 Q14 follows on from Q13, but I've included the necessary information.

In my attempt at the problem, I've calculated the range from firing the shell to where the shell will end up 50m above the water. I just don't know how to calculate the range for the additional 50m.

Or is there an alternative method?

I'm open to all suggestions, thanks in advance.

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A cannon sitting on top of a 50.0m high cliff fires a shell at an angle of [45.0 degrees] with a velocity of 60.0m/s. Determine the new range.

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[juhe]

you can calculate to the top of the parabola, then calculate the second bit to the ground using the horizontal velocity at that point.

 

[locked.on]

I can calculate from the cliff to the top of the parabola and then from the top of the parabola to the point in line with the cliff.

What I can't calculate is the range from the point in line with the cliff to the ground 50m below.

 

[dolbinau]

Is the answer 412 meters?

 

[locked.on]

Yes.

Can you please explain how you reached your solution?

 

[dolbinau]

Yes.

Can you please explain how you reached your solution?

I did it 'kind' of the maths way:

using vertical displacement formula add 50 meters for displacement when T=0 (i.e initially), then solve for T using quadratic formula when Y=0. Then times T by the horizontal component.

 

[locked.on]

Sounds good, thanks for your efforts.

But I'd prefer a Physics method too, seeing as it is a physics question.

 

[Seamus733]

 

[locked.on]

Thanks mate, you are a legend.

Good luck with your HSC too.

 

[Seamus733]

Worked solutions to all of Jacaranda Physics HSC:

http://catalogimages.johnwiley.com.au/Attachment/07016/0701638044/hsc.zip

 

[dolbinau]

What Program do you use to do those maths symbols ? (or was it part of that link)

 

[Seamus733]

What Program do you use to do those maths symbols ? (or was it part of that link)

It's in the link, but I use Mathematica for equations exactly as above in my Chem/Phys/Eng notes.
www.wolfram.com

 

[locked.on]

I didn't think to use the answers, but I'll remember to look into them beforehand.

I have the 1st edition of the book, whereas the solutions are provided for the 2nd edition. I looked at the first page of solutions of Chapter 1 and they were not related at all, so I just forgot about them.

Thanks for the wake up call...

 

[Seamus733]

I didn't think to use the answers, but I'll remember to look into them beforehand.

I have the 1st edition of the book, whereas the solutions are provided for the 2nd edition. I looked at the first page of solutions of Chapter 1 and they were not related at all, so I just forgot about them.

Thanks for the wake up call...

Yeah, I have book 1 at home and book 2 at school. The answers are mixed around for the first book. The first answer you'll find is question 8 for chapter 1.

 

[Continuum]

It's in the link, but I use Mathematica for equations exactly as above in my Chem/Phys/Eng notes.
www.wolfram.com

I have Mathematica, but how come my stuff looks nothing like yours? Your one looks so neat. :uhhuh:

 

[Seamus733]

Don't really know - I adjust fonts and export as html or pdf if that helps?

 

[williamcarr1991]

do you need to pay to use mathematica?