A solid wood door 1.00 m wide and 2.00 m high is hinged along one side and has a total mass of 45.0 kg . Initially open and at rest, the door is struck at its center by a handful of sticky mud with mass 0.600 kg , traveling perpendicular to the door at 12.0 m/s just before impact. Find the final angular speed of the door. Does the mud make a significant contribution to the moment of inertia?

(A) This question invloves the concept of conservation of angular momentum. It is an inelastic or "sticky" collision. So, momentum is conserved and kinetic energy is lost. The final angular momentum will include both masses since the mud sticks to the door.

L=angular momentum = I x w (moment of inertia times angular velocity) = r x p = r x mv (radius times momentum which is mass times velocity)

L(initial)=L(final)

I of the door: The moment of inertia for a thin rectangular plate rotating about an axis on its edge is (1/3)ma2 where a is the distance from the axis or in this case the width of the door.

L(mud)= r x m x v = (.5) x (.7) x (13) = 4.55 kgm2/s = L(initial)

4.55= Ifwf = ((1/3) x mf x a2) x wf = ((1/3) x (mmud + mdoor) x (1)2) x wf =

4.55 = ((1/3) x (43.7) x 1) x wf

wf = .312 rad/sec

(B) No: since the door is so much larger than the mud 43>>>0.7

half of a circle

explanation:

the arrow and the top of the circle is matching together. it is not a polygon because a polygon would always be the same shape. therefore, an half of a circle is called semicircle so you would find the radius of it.

nec chapter 5 contains

c. information on special occupancy areas

nec chapter 6 covers

a. special equipment

which of the following rules contain the words shall or shall not and must be adhered to?

b. mandatory rules

which of the following rules identify actions that are allowed but not required and typically cover options or alternative methods?

c. optional rules

which of the following serves as the introduction to the nec and provides an overview of the book?

a. nec article 90

organizations that test products for safety are

c. nrtls

the nec is published by the

a national fire protection association

the nec is divided into

b. 9 chapters

the nec provides informative annexes for

c. informational materials and examples

two terms from nec article 100 that trainees should become familiar with are

b. labeled and listed

explanation: