When thinking about human swimmers, which model of fluid drag most appropriate?
estimate the reynolds number for a human swimming in water. approximate the human as a sphere of radius 0.5m, swimming at a speed of about 11m/s. the density of water is approximately 1000kg/m³ and its viscosity is 0.001n/m².s.
a. re = 50,
b. re = 5 x 10⁵,
c. re = 2 x 10⁴,
d. re = 0.5,
e. re = 5 x 10⁵,

An object is dropped from a tower, 400 ft above the ground. the object's height above ground t seconds after the fall is s(t)equals400 minus 16 t squared. determine the velocity and acceleration of the object the moment it reaches the ground. the velocity of the object the moment it reaches the ground is nothing ft/s.

While studying chemical reactions and conservation of matter, sarah's class conducted a variety of experiments. sarah and her lab partner found the mass of a wax candle and placed the candle in a flask. the students lit the candle and let it burn to completion. all that was left was wax and charred candle wick. per their teacher's instructions, the students found the mass of the products. their data can be seen in the data table. formulate a hypothesis the students could test to explain why the experiment did not support the law of conservation of matter. a) the students could repeat the experiment using different candles; there might have been a flaw in the candle. b) the experiment should be repeatable. the students should run several trials and then take an average of the after mass in each trial. c) the students should have someone in the class check their measurement skills as they repeat the experiment. they may have made an error using the balance. d) the students should burn the candle in a container that has some type of lid so that any gas that is a product of the reaction can be contained and massed. submit

Awhite-blue star is hotter than a red star. select the best answer from the choices provided true or false