How much gravitational potential energy does an object have if it is located 20 m above the point that we define as O height and has a mass of 10 kg

Explanation:

PE = mgh where m is the mass in kg, g is the pull of gravity which is 9.8, and h is the height of the object above the point to which it could possibly fall, measured in meters. Plugging in:

PE = 10(9.8)(20) so

PE = 1960 J

This should be rounded to 1 sig fig according to the rules of sig fig and your numbers here, but I imagine you're not following them all that much. It should be 2000 J

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

spectral lines lyman is one set