PROBLEMS 2-i10 You\'re standing on the roof of your sci- ence building, which is

Question

PROBLEMS 2-i10 You're standing on the roof of your sci- ence building, which is 10.0 meters above the ground. You have a rock in your hand, which you can throw with a maximum speed of 10.0 m/s. (a) How long would it take for the rock to hit the ground if you released the rock from rest? (b) How long would it take for the rock to hit the ground if you threw the rock straight downward? (c) How long would it take for the rock to hit the ground if you threw the rock straight upward? (d) If you threw the rock straight upward, how high would it get above the ground?

Explanation / Answer

(a) This part is ambiguous...rock is thrown in which direction ????

I am assuming, it is just released.

x = ut + 1/2at2

x = 1/2at2

t = sqrt (2x / a)

t = sqrt (2*10 / 9.8)

t = 1.4285 sec

(b) x = ut + 1/2at2

0 = 10 -10t - 4.9t2

4.9t2 + 10t - 10 = 0

t = 0.735 sec

(c) at max height, v = 0

therefore,

v2 - u2 = 2gh

0 - 100 = 2*(-9.8)h

h = 5.1 m

Now, rock needs to cover a total of 10 + 5.1 m = 15.1 m to hit the ground, and initial velocity is zero

therefore,

15.1 = 1/2at2

t = 1.755 sec

(d) from the ground, it would be 15.1 m

(c)

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

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