Eva is in a closed, dark room. she uses her arm muscles to turn on a lamp. when she moves her hand closer to the lamp, the light heats her hand. the light bounces off the pages of a book and into her eyes.

if this room is a closed system, what happens to the total amount of energy in the room?

a.
it remains constant.

b.
it decreases.

c.
it increases, then decreases.

d.
it increases.

The uniform slender bar rests on a smooth horizon- tal surface when a force f is applied normal to the bar at point a. point a is observed to have an initial acceleration aa of 20 m/s2, and the bar has a corre- sponding angular acceleration of 18 rad /s2. deter- mine the distance b.

How many atoms of nitrogen are in the chemical formula ni(w on

A5 foot by 5 foot box culvert is buried 6 feet beneath the surface of the ground. a crosssection of this very long culvert (into and out of the page) is illustrated below. assume that the soil in which the culvert is buried has the following properties: jt = 120 pcf, w = 12%, ko = 0.50, ka = 0.33, and kp = 3.00. calculate the total horizontal force per unit length of culvert (fh) felt on one of the vertical faces of the culvert.