# Thread: Stuck on part 2 on this derivative question

1. ## Stuck on part 2 on this derivative question

A bullet is fired such that is follows a part given by x = 315t, y = 65t -4.9t^2
PART 1
Find the Magnitude and direction of the velocity with t-2.5 sec.
Vx = 315 and Vy = 40.5 with R=317.6 and Angle 7.3 degree.

PART 2
Now it asks find the time at which the bullet in this question would have a y component of 0, then find the the magnitude and firection of the velocity at that time. t>0

Answer is 321.6 and angle of -11.66 degree.
I am stuck on part 2 of this question. HELP, Thanks, Jo

2. to see when the y component is 0, just set y=0 and solve for t.

3. Well I was thinking that, but thought it was more, thank you for your reply.