Which of the following has the largest R-value? (Use the table of R-values on page 111 of the textbook.)
A. 25 mm of air space with a reflective surface on the inside of the wall cavity
B. 50 mm of expanded polystyrene
C. 25 mm of fibreglass
D. 25 mm of rigid urethane foam

B?

Explanation:

I could be right, I could be wrong...

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.

the answer is a. hope this .