Lesson: Forces that Resist Motion
In this lesson, we will learn how to compare friction and drag forces, and also explain how the variable drag force on an object results in a terminal velocity.
Sample Question Videos
Worksheet: 14 Questions • 4 Videos
Which of the following statements about drag and friction is not correct?
An object with a mass of 135 kg moves through a gas at an initial velocity of 2.5 m/s. The surface of the object that faces the oncoming gas is square, as shown in the diagram. The gas has a density of 0.75 kg/m3.
What is the momentum of the object before it has displaced any gas?
What volume of gas is displaced in one second by the object?
What mass of gas is displaced in one second by the object?
What momentum is given to the gas in one second, assuming that the object moves at 2.5 m/s for the whole of the second?
What would the velocity of the object be after moving through the gas for one second if the object lost the same amount of momentum as would be gained by the gas had the object maintained a constant velocity of 2.5 m/s through the gas?
A metal bead has a cross-sectional surface area of 0.001 m2. The bead starts at rest and falls a distance of 5 cm through a fluid with a density of kg/m3.
What total mass of fluid does the bead displace as it falls through 5 cm?
If the acceleration of the bead as it falls is 8.2 m/s2, how much average force does the bead exert on the fluid that it displaces?