Question

Two equal drops of water are falling through air with a steady velocity v. If the drops coalesced, what will be the new velocity?

Answer 1

When the two equal drops fall  the certain change happens

• When the two drops coalesces one thing remain constant that is the volume of the drops.
• Then they merge with each other and form one bigger drop.
• To find the new velocity of the bigger drop
• Let r be the radius of the drop before it combine
• And R be the radius after combination.
• 2×4πr³/3=4πR³/3
• On simplifying we get R³=2r
• As the change in velocity
• V₁/v=R²/r²
• V₁=R²v/r²
• That is the new velocity value