Usain Bolt ran 100 m in 9.58 s, reaching a final speed of 12.43 m/s. What was his acceleration?

1.3m/s²

Explanation:

Given parameters:

Distance  = 100m

Time taken  = 9.58s

Final speed  = 12.43m/s

Unknown:

Acceleration = ?

Solution:

Acceleration is the rate of change of velocity with time; to solve this problem, we apply one of the motion equation;

   v  = u + at

v is the final speed

u is the initial speed

a is the acceleration

t is the time

 u  = 0m/s

Insert the parameters and solve;

      12.43  = 0 + a x 9.58

     12.43  = 9.58a

       a  =   = 1.3m/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.