Question

1.You are stuck on a cliff and want to know how far to the bottom. You drop a rock and time how long it takes to hit the ground. If the rock takes 10 seconds to hit the ground how high is the cliff? How fast was the rock going to impact?
2. You throw a plate off your roof with a speed of 10.0 m/ s. 4 seconds later it hits the ground? How far?
3. You throw a baseball straight up at 40 m/ s and it reaches its peak after 4 seconds. What is its speed when it falls back into your hand? What is it displacement? What distance has it traveled?

Answer 1

hf=hi+vi*t+1/2 gt^2

g=-9.8m/s^2

in the first, hf=0,hi=?, vi=0
in the second, vi=-10,hf=0, hi=?

in the third, the velocity at the top is zero.

Vf=vi+gt
vf=40-9.8(8)
displacement =0 if it returns to your hand.

distance? twich the height..
hf=hi+40*t+1/2 g t^2 g=-9.8m/s^2