Grade 12 Physics - Motion/acceleration.

[christinecrun]

Homework Statement

A rock is shot straight up from a slingshot with an initial speed of 30 m/s. When it's exactly halfway to the top of its flight, a second rock is shot straight up from the same spot. The second rock reaches the first rock just as the first rock reaches its apex (highest point).

1.What is the "muzzle" speed of the second rock? (The muzzle speed is the speed at which the rock leaves the sling shot.)
2.What maximum height does the second rock reach?

The Attempt at a Solution

I don't even know where to start :S
Please help!
thanks :)

Homework Equations

The Attempt at a Solution

 

[kmikias]

what do you know about something at maximum height ...something is gone have value of 0 and you have to try to think the two rocks as one formula ...which means you have to set it equall .because the second rock reaches the first rock at highest point.which is same height.