Part a and b please (5%) Problem 24: Standing at the base of one of the cliffs o

Question

Part a and b please

(5%) Problem 24: Standing at the base of one of the cliffs of Mt. Arapiles in Victoria, Australia, a hiker hears a rock break loose from a height of 130 m. He can't see the rock right away but then does, I.I s later ** 50% Part (a) How far above the ground, in meters, is the rock when the hiker starts to see it? Neglect the time for the sound to reach the hiker Grade Summary Deductions Potential y = 5.9291 4% 96% sinO cotanasin0 acoso atanO acotan) sinh(0 cosh0tanh0 coho Submissions Attempts remaining: 4 (4% per attempt) detailed view 78 9HOME 4% 0 END Degrees O Radians O BACKSPACE DEL CLEAR Submit Hint Feedback I give up! Hints: 4% deduction per hint. Hints remaining: 4 Feedback: 5% deduction per feedback D 50% Part (b) How much time, in seconds after he notices the falling rock, does he have to move before the rock hits his head? Ignore the height of the hiker.

Explanation / Answer

a) from the equation y = ut+1/2at^2

u = 0

y = 1/2gt^2

y = 1/2*9.8*1.1^2 = 5.9 m

h = 130-5.9 = 124.1 m

b) t = sqrt(2*130/9.8) = 5.15 sec

the time to move is 5.15-1.1 = 4.05 sec

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