7.2k views
4 votes
A rock is dropped off a cliff that is 138 m tall. How long will it take to hit the ground? What is the rock’s final velocity?

User Caylin
by
7.4k points

1 Answer

4 votes
y = (1/2).g,t² + v₀.t, where:
y = distance = 138 m
g = 9.8 m/s² (gravity)
v₀ = initial speed = 0

138 = (1/2)(9.8).t² + 0 →138= 4.9.t² and t² = 138/4.9 = 28.16 and t = 5.3 s

Final speed V(final) = V(initial) + gt

V(final) = 0 + 9.8(5.3) = 51.94 m/s ≈ 52 m/s

User AdamCrawford
by
8.1k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories