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# Impossible Mechanics Question! watch

1. Question - Some of the year 13 students have moved into a position 7m above you on the balcony. They're about to launch pineapples horizontally a some annoying year 10s. You are 3m away from the year 13s

A - What is the minimum velocity the pineapples need in order to miss you?

B - The year 10s are 28m away from the year 13s. Calculate the initial velocity the pineapples need.

NEED HELP PLEASE !
2. (Original post by Ronnieee)
Question - Some of the year 13 students have moved into a position 7m above you on the balcony. They're about to launch pineapples horizontally a some annoying year 10s. You are 3m away from the year 13s

A - What is the minimum velocity the pineapples need in order to miss you?

B - The year 10s are 28m away from the year 13s. Calculate the initial velocity the pineapples need.

NEED HELP PLEASE !
First one is a bit confusing, as in theory it could be 0, but I may have just misunderstood the question.

For part B, do suvat vertically to work out the time taken to fall 7m. Once you have the time, do suvat horizontally to work out the speed needed to travel 28m in the time you just worked out.
3. (Original post by tom28)
First one is a bit confusing, as in theory it could be 0, but I may have just misunderstood the question.

For part B, do suvat vertically to work out the time taken to fall 7m. Once you have the time, do suvat horizontally to work out the speed needed to travel 28m in the time you just worked out.

How? For part b :-

S = +7m
U = where do i get this from?
V = where do i get this from?
A = -9.81m/s
T = where do i get this from?

I need more than 2 numbers to so the calculations or am i missing something
4. (Original post by Ronnieee)
How? For part b :-

S = +7m
U = where do i get this from?
V = where do i get this from?
A = -9.81m/s
T = where do i get this from?

I need more than 2 numbers to so the calculations or am i missing something
They are launched horizontally, so the initial vertical velocity = 0. If you are taking downwards as positive, then both displacement and acceleration will be positive.

so s=ut+0.5at^2, leaving you with a quadratic to solve.

Hope this helps.
5. (Original post by tom28)
They are launched horizontally, so the initial vertical velocity = 0. If you are taking downwards as positive, then both displacement and acceleration will be positive.

so s=ut+0.5at^2, leaving you with a quadratic to solve.

Hope this helps.

Oh yeah i meant to say :-
S = -7m
U = where do i get this from?
V = where do i get this from?
A = -9.81m/s
T = where do i get this from?

So your saying that if i launch horizontally the initial velocity will be zero all the time? Is this EVERY time for all horizontal launches?
6. What legend wrote this question?
7. (Original post by Ronnieee)
Question - Some of the year 13 students have moved into a position 7m above you on the balcony. They're about to launch pineapples horizontally a some annoying year 10s. You are 3m away from the year 13s

A - What is the minimum velocity the pineapples need in order to miss you?

B - The year 10s are 28m away from the year 13s. Calculate the initial velocity the pineapples need.

NEED HELP PLEASE !
A) not a question
B) not a question
8. (Original post by Ronnieee)
Oh yeah i meant to say :-
S = -7m
U = where do i get this from?
V = where do i get this from?
A = -9.81m/s
T = where do i get this from?

So your saying that if i launch horizontally the initial velocity will be zero all the time? Is this EVERY time for all horizontal launches?
If it is launched horizontally, then initially it will only have a horizontal component of speed.
9. You are 3m away from the year 13s Is 3m the horizontal displacement? If yes then the solution, according to me, is as follow:

Taking downwards as positive,
s = ut + 0.5at^2
7 = 0*t + 0.5*9.8*t^2
7 = 4.9t^2
t=1.195s

s=vt
3=v * 1.195
v = 2.5099...s ( initial velocity )

B - The year 10s are 28m away from the year 13s. Calculate the initial velocity the pineapples need.
Away horizontally or vertically or with an angle with the vertical/horizontal?
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10. (Original post by raheem94)
[U]You are 3m away from the year
s=vt
3=v * 1.195
v = 2.5099...s ( initial velocity )
The displacement is 7m not 3m
11. (Original post by 117r)
What legend wrote this question?

Lol... there are funnier questions on the sheet. A lot of naan bread throwing.
12. (Original post by Ronnieee)
The displacement is 7m not 3m
7m is the vertical displacemet. I am asking you whether 3m is the horizontal displacement or the modulus of horizontal and vertical displacement?
13. (Original post by Ronnieee)
Lol... there are funnier questions on the sheet. A lot of naan bread throwing.
Just out of interest, what are these other questions, and do they involve cheeseburgers and / or milkshakes?
14. (Original post by raheem94)
7m is the vertical displacemet. I am asking you whether 3m is the horizontal displacement or the modulus of horizontal and vertical displacement?
it is the horizontal displacement
15. surely you need to say how tall you are.
16. (Original post by Ronnieee)
it is the horizontal displacement
So my answer to part 'a' will probably be correct.
What does 28m away in part 'b' tells, the horizontal or vertical displacement or the modulus of both?

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