Arunner achieves a velocity of 11.1 m/s, 9 sec after he begins. what is his
acceleration?
given:
equation:
plug in:

1.23 m/s²

Explanation:

Given:

v₀ = 0 m/s

v = 11.1 m/s

t = 9 s

Find: a

Equation:

v = at + v₀

Plug in:

11.1 m/s = a (9 s) + 0 m/s

a = 1.23 m/s²

The runner's acceleration is 1.23 m/s².

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.