I need help with a couple of questions.

13) If a glass is knocked off a table that is 1.4 m tall, how long does it take for the glass to get to the ground? I have to use the GUESS method which is: Givens, Unknown, Equation, Substitute and Solve.

14) If a ball is thrown off of a 123 m cliff at a speed of 18 m/s, how far from the base of the cliff is the ball?

Question

I need help with a couple of questions.

13) If a glass is knocked off a table that is 1.4 m tall, how long does it take for the glass to get to the ground? I have to use the GUESS method which is: Givens, Unknown, Equation, Substitute and Solve. 

14) If a ball is thrown off of a 123 m cliff at a speed of 18 m/s, how far from the base of the cliff is the ball?

jessicalynn1231 · Answer

13) G: $$y _{f}-y _{i}=1.4m$$ $$a=-9.81m/s ^{2}$$ $$v _{i}=0$$
U: time
E:$$ y _{f}-y_{i}=v _{i} (t)+.5(a)(t^2)$$
S: $$1.4=0(t)+.5(-9.81)(t^2)$$
Use your algebra skills and you should get .534 seconds