What is the equation of motion for two cubes colliding in vertical motion?

[heaven eye]

child play with cubes , he threw first one vertically to up with velocity of (v), after five seconds he threw second cube vertically to up with the same velocity , two cubes collided at 9 meter height what the velocity of two cube? (they are the same!)


actually i don't know but final answer, i need help please

and thank you all again , again , and again .

 

[The Bob]

child play with cubes , he threw first one vertically to up with velocity of (v), after five seconds he threw second cube vertically to up with the same velocity , two cubes collided at 9 meter height what the velocity of two cube? (they are the same!)

You want to use $$s = ut + \frac{1}{2}at^2$$ and $$v^2 = u^2 + 2as$$ setting s to 9 each time. Then the two equal each other and you can find a time as you know the acceleration and the time in each case.

The Bob (2004 ©)

 

[dextercioby]

You should write the equation of motion in vector form

$$\vec{r}(t)=\vec{r}_{0}+\vec{v}_{0}t+\frac{1}{2}\vec{a}t^{2}$$

and then choose an axis along which the movement takes place,an origin for this axis, then a sense on this axis and then do the projection of the vector equality on this axis...

This is just the beginning,but it's essential.

Daniel.