An 8.0-kg history textbook is placed on a 1.25-m high desk. how large is the gravitational potential energy of the textbook-earth system relative to the desktop?

Gravitational potential energy of the textbook-Earth system relative to the desk = 98 N/m

Given that,

Mass of history book = 8kg

height of book from ground = 1.25m

acceleration due to gravity = 9.8m/s²

where ,

m = mass of object(book)

g = acceleration due to gravity

h = the altitude of the object.

GPE = 8(9.8)(1.25)

       = 98 N/m

So, gravitational potential energy of the textbook-Earth system relative to the desk = 98 N/m

i think it would be 80 km/h because 30 + 50 = 80 (sorry if this not the right answer i'm trying my best)