This is a follow from a post i made yesterday. The question is:(adsbygoogle = window.adsbygoogle || []).push({});

2 particles are projected vertically up one after another from the same point at same initial speed u. T is the time interval between the 2 projections, where T<2u/g. Find what further time elapses before the particles collide, and find their speeds immediately before impact.

The equations i have found so far are for distance travelled

x= -0.5gt^2 + ut.

However i have realised this formula is for the distance the particle has travelled rather then the height reached. Since i need to find the time when the particles will collide (ie when they are at the same height) i am stuck as i think the formula is no use?! Please help

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Projectile please help

**Physics Forums | Science Articles, Homework Help, Discussion**