Your friend's Frisbee has become stuck 19m above the ground in a tree. You want to dislodge the Frisbee by throwing a rock at it. The Frisbee is stuck pretty tight, so you figure the rock needs to be traveling at least 5.4m/s when it hits the Frisbee.
If you release the rock 1.7m above the ground, with what minimum speed must you throw it?