A box of textbooks is on the middle shelf in the bookroom 1.3 m from the floor. If the janitor relocates the box to a shelf that is 2.6 m from the floor, how much work does he do

Explanation:

Work done by janitor = increase in potential energy of book

Potential energy = mgh , m is mass  , h is displacement in height and g is acceleration due to gravity .

here displacement in height of book = 2.6 - 1.3 = 1.3 m

so h = 1.3 m

m = mass of the box

increase in potential energy of box = m x 9.8 x 1.3

= 12.74 m

Work done by janitor = 12.74 m Joule .

radiation

explanation:

heat is transmitted by radiation

the answer is a. hope this .