i believe it's always better to visualize the problem.
the particle movement is identical. everything is the same except for the time of launch.
let's call:
T0 = time of launching particle1.
gap = the gap between the launches.
T1 = time of collision.
so on the equation of particle2 just place...
try drawing a graph of height as a function of time for both particles.
(time is the horizontal axis, height is the vercital axis)
since there are no other forces at play here (besides gravitation) then you can draw the movement of particle1 as a parabula. the same goes for particle2.
after...
notice that the LHS equals to:
[ F'yz - F'zy , F'xz - F'zx , F'xy - F'yx ]
in differential math, F'ab = F'ba (where a,b = x,y,z)
so you get [0 , 0 , 0] on the LHS.
hope this helps...
this is perfectly clear! thanks very much indeed :)
so this means that the system's energy is conserved although the collision occurs because it's an elastic collision? hope i got this right.
number 1:
take another look at the equation (AB)(AY) = (AC)(AX).
you can also write it like this:
(AB)/(AC) = (AX)/(AY)
does this reminds you of something? (hint: yes)
number 2:
forget about the length of BD... i was going for trigonometric approach...
see the size of the triangle ABC. how...
clue for the 1st:
notice that the triangle's size can be calculated in more than one way.
clue for the 2nd:
the triangle ABD. what kind of triangle is it? what can you tell about the length of BD?
since this is a parabula, you can find its roots (the points where f(x)=0). there are always 2 roots.
roots equations: (-B +- sqrt(B^2 - 4AC)) / 2A
A is the coefficient of X^2
B is the coefficient of X^1
C is the coefficient of x^0
the parabula has 3 different possible conditions:
#1...
simple enough. this equation represents a curve called parabula.
try drawing this curve on XY surface.
try with different k values such as: k=0, k=1, k=-1... and see how this changes the curve.
*please note that k=0 doesn't match your question because if does get the value of 0 and you're...
another approach, given "easy" equations is to draw the equations on X,Y plane and see how many intersections you get. the number of intersection is the number of (x,y) answers you'll get.
i.e. if you're drawing shows no intersections this means you got no answer...