What is the Time of Collision for Two Vertically Launched Objects?

[Mightiestmike]

Pat shoots an arrow vertically upward with an initial speed of 25 m/s. When it is exactly halfway to the peak of its flight, he shoots a second arrow vertically upward from the same spot. They collide just as the first arrow reaches its highest point.

(A) What is the Launch Speed of the Second Arrow?
(B) What Maximum Height does the second arrow Reach?


Brad is on Top of a 20m Cliff. Below he spots Tom. He drops a stone off the cliff. At the same time Tom throws a second stone vertically upwards with an initial velocity of 30 m/s. Assuming that he threw the rock hard enough, at what time will the two stones meet?

 

[courtrigrad]

read the sticky...show your work

 

[Mightiestmike]

Givens:
Via1 = 25 m/s
a = -9.81m/s^2
Vfa1 = 0 m/s
Via2 = ?
da1 = ?

Vf^2 = Vi^2 + 2ada1
0^2 = 25^2 + 2(-9.81)da1
-625 = -19.62da1
da1 = 31.85524 m

Therefore Half the height = 15.92762 m

Need Help Continuing

 

[dextercioby]

Okay now compute the times...How much time will the second arrow require to reack the peak and how is that related with the time the first arrow travels the same distance?

Daniel.