S=ut 4% at? -25m = 12 + + / + domist?
-25m= 12t + (-5 mist)
-25m= 12m &t -Smist?
5 m/st² - 12m/gt - 25 m=0
t= 3.73 sec​

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.

the part of the wave he is travelling on is the crest