Question

a stone dropped from the height of a tower of height 300 metres splashes into a pond of water at its base. When will the sound of the splash be heard at the top?
{ g= 9.8m/s and velocity of sound= 340 m/s}​

Answer 1

(--) ᴀɴsᴡᴇʀ: (--)

ᴀs ɢɪᴠᴇɴ ʜᴇɪɢʜᴛ ᴏғ ᴛʜᴇ ᴛᴏᴡᴇʀ = 300ᴍ , ɪɴᴛɪᴀʟ ᴠᴇʟᴏᴄɪᴛʏ ᴏғ sᴛᴏɴᴇ, ᴜ = 0 ᴍ/s ,, sᴛᴏɴᴇ ᴡɪʟʟ ғʀᴇᴇ ғᴀʟʟ ᴜɴᴅᴇʀ ᴛʜᴇ ᴇғғᴇᴄᴛ ᴏғ ɢʀᴀᴠɪᴛʏ, sᴏ ᴀᴄᴄᴇʟᴇʀᴀᴛɪᴏɴ =ɢ ʟᴇᴛ ᴜs ᴄᴏɴsɪᴅᴇʀ, ᴛɪᴍᴇ ᴛᴀᴋᴇɴ ʙʏ sᴛᴏɴᴇ ᴛᴏ ʀᴇᴀᴄʜ ᴛʜᴇ ᴘᴏɴᴅ, ᴛ1 = ? ʜ = ᴜᴛ1 + (1/2)ɢᴛ12 300 = 0 + (0.5 *x 9.8 x ᴛ12) ᴛ12 = 61.22 ᴛ1 = 7.82 s ɴᴏᴡ ʟᴇᴛ ᴜs ᴄᴏɴsɪᴅᴇʀ ᴛɪᴍᴇ ᴛᴀᴋᴇɴ ʙʏ sᴏᴜɴᴅ ᴛᴏ ʀᴇᴀᴄʜ ᴛʜᴇ ᴛᴏᴘ ᴏғ ᴛᴏᴡᴇʀ ɪs ᴛ2

ᴛ2 = ʜ/ᴠ = 300/340 = 0.88 s 7.82 + 0.88 = 8.7 s ᴛᴏᴛᴀʟ ᴛɪᴍᴇ, ᴛ= ᴛ1 + ᴛ2 = 7.82 +0.88=8.7 s

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