Physics Problems: Calculating Height and Speed in Real-Life Situations

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To solve the first physics problem, the height of the cliff can be calculated using the total time of 2.5 seconds, subtracting the time it takes for sound to travel back up, which is determined by the speed of sound at 340 m/s. For the second problem, the first stone's fall time is denoted as t, while the second stone's fall time is t - 2.3 seconds, allowing for the formation of equations based on their simultaneous landing. The height of the building can be derived from the equations of motion for both stones, and their final speeds can be calculated using kinematic formulas. Understanding the relationship between the time of fall and the height will facilitate solving these problems. Clear equations and a systematic approach will lead to the correct answers for both scenarios.
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I am stuck on these 2 physics problems. Can anyone help?

1) A rock is dropped from a sea cliff and the sound of it striking the ocean is heard 2.5 s later. If the speed of sound is 340 m/s, how high is the cliff?

2) A first stone is dropped from the roof of a building. 2.30 s after that, a second stone is thrown straight down with an initial speed of 35.0 m/s, and it is observed that the two stones land at the same time.
(a) How long did it take the first stone to reach the ground?
(b) How high is the building?
(c) What are the speeds of the two stones just before they hit the ground?

Any help on how to get started would be great. Thanks in advance.
 
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Can you think of an expression to find the time while the stone is falling down? Now can you think of one for the time while the sound is traveling back up to the top of the cliff?
 
2) Do note that the time the first stone takes to fall down is t while with the second stone it's t-2.3s. This should make forming the equation easier.
 

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