1 Harry is now totally panicked about the second task, since neither he nor Hermione can figure out how Harry can breathe underwater. 2  The night before the task, Fred and George show up with a message from Professor Dumbledore for Hermione and Ron. The night before the task, Fred and George show up with a message from Professor Dumbledore for Hermione and Ron. 2  Professor Dumbledore needs them for something. 3  Harry just keeps reading and reading, hoping  next book ... in the next one ... the next one  (26.72). 4  Finally, he nods off without realizing it.
The net force on the object then, is zero, and the result is that the velocity of the object remains constant. Terminal velocity is the highest velocity attainable by an object as it falls through a fluid (air is the most common example, but the concept applies equally to any fluid). It occurs when the sum of the drag force (Fd) and the buoyancy is equal to the downward force of gravity (FG) acting on the object.
The terminal velocity speed changes depending on the weight of the object falling, its surface area and what itâs falling through. For example, a feather doesnât weigh much and presents a very large surface area to the air as it falls. So its terminal velocity speed is much slower than a rock with the same weight.