Projectile Motion Q (1 Viewer)
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Carrotsticks
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Find their respective Cartesian Equations, then solve them simultaneously (for the two paths to meet).
Carrotsticks
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Not quite. It would just be x(dot)=-20cos45.Just checking, would the horizontal velocity of the second ball be given by the following?
You add the +30 afterwards when you integrate one more time, to get x (since t=0, x=30)
D94
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More often than not, it comes down to your equations of motion and whether they are correct or not. After that, it's about thinking what is happening. What are your equations of motion? i.e. x = ..... y = ..... etc.
gr_111
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OK this is what I got for the equations of motion:
Projectile A (from the origin)
x.. = 0
x. = 15cos60
x = 15tcos60
y.. = -10
y. = -10t + 15sin60
y = -5t^2 +15tsin60
Projectile B (from x=30)
x.. = 0
x. = -20cos45
x = -20tcos45+30
y.. = -10
y. = -10t + 20sin45
y = -5t^2 +20tsin45
Projectile A (from the origin)
x.. = 0
x. = 15cos60
x = 15tcos60
y.. = -10
y. = -10t + 15sin60
y = -5t^2 +15tsin60
Projectile B (from x=30)
x.. = 0
x. = -20cos45
x = -20tcos45+30
y.. = -10
y. = -10t + 20sin45
y = -5t^2 +20tsin45
gr_111
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Don't worry, got this out finally. Turns out the best way is to equate the x displacements to find a time where they are at the same displacement. Sub the time into the x and y displacements to see what times they arrive at the points and hence whether they collide.
Last edited:
davidgoes4wce
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I am still stuck on this question been spending a couple of hours on it for curiosity sakes.
My first question to anyone that has attempted this, are the diagrams shown on Q25 misleading? First of all I worked out the height of the 15m/s (at 60 degrees) having a max height of 8.43 m and the second ball of 20 m/s (at 45 degrees) to be a height of 10.0 m.
The diagrams show that the 20m/s has a lower height which I believe is wrong.
Thoughts ? Opinions?
My first question to anyone that has attempted this, are the diagrams shown on Q25 misleading? First of all I worked out the height of the 15m/s (at 60 degrees) having a max height of 8.43 m and the second ball of 20 m/s (at 45 degrees) to be a height of 10.0 m.
The diagrams show that the 20m/s has a lower height which I believe is wrong.
Thoughts ? Opinions?