(1096) Problem 10: A rock takes 2.2 s to hit the ground when it is thrown straig

Question

(1096) Problem 10: A rock takes 2.2 s to hit the ground when it is thrown straight up from the cliff with an initial velocity of , m/s. 50% Part (a) Calculate the height of the cliff in m. Correct Answer h= 6.336 Student Answer h = 6.3 Grade Detail Student Feedback Correct Final Answer C Submission History Hints Feedback Answer h=68 590 5% 09% 0% h=-68 0% h-63 10% 09% Totals 50% Part (b) How long would it take to reach the ground if it is thrown straight down with the same speed? All coet 2017 Expert TA, LLC

Explanation / Answer

10. time taken to hit the ground, t = 2.2 s

initial velocity upwards, v = 7.9 m/s

a. let the height of the cliff be h

then using

h = vt - 0.5gt^2

h = 7.9*2.2 - 0.5*9.81*2.2^2

h = -6.3602

so height of cliff is 6.3602 m

b. time taken, when it is thrown dows with same speed be t'

then

h = vt - 0.5gt^2

-6.3602 = -7.9*t - 0.5*9.81*t^2

4.95t^2 + 7.9t - 6.3602 = 0

solving for t

t = 0.593 s

Related Questions

Navigate

• Browse (All)
• Browse #
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.