- #1
Let It Be
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1. When a kid drops a rock off the edge of a cliff, it take s 4.0s to reach the ground below. When he throws the rock down, it strikes the ground in 3s. What inital speed did he give the rock?
ΔX=ViTf + 1/2ATf^2
H=1/2gt^2
Vf^2=Vi^2+ 2AΔX
3. Hi everyone! I know that when the kid drops the rock, you can use the free fall equation- H=1/2gt^2; but the problem doesn't say the height of the cliff and I don't know "g", unless it's just 9.8? Also, I don't know inital velocity, so I just don't know how to go about this! If anyone can help me, that'd be much appreciated!
ΔX=ViTf + 1/2ATf^2
H=1/2gt^2
Vf^2=Vi^2+ 2AΔX
3. Hi everyone! I know that when the kid drops the rock, you can use the free fall equation- H=1/2gt^2; but the problem doesn't say the height of the cliff and I don't know "g", unless it's just 9.8? Also, I don't know inital velocity, so I just don't know how to go about this! If anyone can help me, that'd be much appreciated!