A pendulum of mass 18 kg is released from rest at some height, as shown by point A in the image below. At the bottom of its arc at point B, it is traveling at
a speed of 17 m/s. What is the approximate amount of energy that has been
lost due to friction and air resistance? (Recall that a=98 m/s2

By the work-energy theorem, the total work done on the mass as it swings is

W = ∆K = 1/2 (18 kg) (17 m/s)² = 153 J

No work is done by the tension in the string, since it's directed perpendicular to the mass at every point in the arc. Similarly, the component of the mass's weight mg pointing perpendicular to the arc also performs no work.

If we ignore friction/drag for the moment, the only remaining force is the parallel component of weight, which performs mgh = (176.4 N) h of work, where h is the vertical distance between points A and B.

Now, if w is the amount of work done by friction/air resistance, then

(176.4 N) h - w = 153 J

If you know the starting height h, then you can solve for w.

with the invention of the automobile, the woman of the house could drive to the store and get groceries. women were also free to socialize more. during world war ii women were allowed to work in factories to the war effort and could drive to work or ride mass transit buses to their jobs.

another example of kinetic energy would be,

kinetic energy   >     moving energy

answer   >   letter choice (c),   a hammer falling off a table.

hope that !                                         : )