Question

...............................................................................................

You throw a rock from the upper edge of a 70.0-m vertical dam with a speed of 23.0 m/s at 65.0° above the horizon 1) How long after throwing the rock will you see it hit the water? (Neglect any effects due to air resistance.) (Express your answer to three significant figures.) s Submit You currently have O submissions for this question. Only 10 submission are allowed You can make 10 more submissions for this question 2) How far from the bottom of the dam does the rock land? (Neglect any effects due to air resistance. (Express your answer to three significant figures.) m Submit You currently have O submissions for this question. Only 10 submission are allowed. You can make 10 more submissions for this question

Answer 1

1)

using second kinematical eqn

s = ut + 1/2 at^2

s = displacement = -70m .. from top to water
u = initial speed = 23sin65 = 20.85 m/s .. taking vertical motion only
a = -9.8 m.s^2

-70 = 20.85 x t - 4.9 x t^2
solve the above quadratic

t = 6.464 sec

2)

x = speed x time

speed = 23cos65 = 9.72 m/s ... taking horizontal motion only

x = 9.72 x 6.464 = 62.83 m

upvote if helps