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Mechanics - Projectiles - Terribly Stuck! watch

1. Use g= 10ms-2

A firework is buried so that its top is at ground level and its projects sparks all at a speed of 8ms-1. Air resistance may be neglected.

Calculate the height reached by a spark projected vertically and explain why no spark reach a height greater than this.

I've tried answering this question but I just get a height of 8m; however this is the wrong answer. Can some please explain which SUVAT equation I need to use and why
2. You know at maximum height it's velocity will be zero. You know it's initial velocity. You know acceleration. That is three of four parts of
3. (Original post by D-Day)
You know it's initial velocity.
I do?
I didn't think I did.
I've just tried it with zero and thats not working out either.
4. (Original post by high_maintenance_girl)
I do?
I didn't think I did.
I've just tried it with zero and thats not working out either.
(Original post by high_maintenance_girl)
and it projects sparks at a speed of 8ms-1
You do.
5. (Original post by D-Day)
You know at maximum height it's velocity will be zero. You know it's initial velocity. You know acceleration. That is three of four parts of
that's usually written as , if it makes it any simpler. you've got a, u and v, you need s.
6. (Original post by imtired)
that's usually written as , if it makes it any simpler. you've got a, u and v, you need s.
Different country, different letters apparently. Forgive my not being British
7. (Original post by D-Day)
You do.
I see I see. I just need things spelling out to me lol

But I still got a problem

v = 0
u = 8
a = - 10

Using v = u + at, that gives time to reach max height as 0.8 seconds

Then if i substitute all those values into s = ut + (0.5 x a x t^2)
I get 3.2 - 3.2 = 0

I've probably just made a silly mistake; can you see what I'm doing wrong?
8. (Original post by high_maintenance_girl)
I've probably just made a silly mistake; can you see what I'm doing wrong?
I was lol
I found my mistake and I've corrected it.
Thanks for the help D-day!

And I was a bit worried about the symbols but I just assumed that was higher level ways of writing the same thing lol.
9. V^2 = U^2 + 2as-----> u = 0

64/20 = s = 3.2m but you probably figured out that already but i am bored lol

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