Let us write the given data first

GIVEN:

Total distance of the race (S) = 100 m

Time taken to complete the race (T) = 9.8 sec

TO FIND:

Speed at which athlete completed the race = ?

HINT GIVEN:

Athlete ran with uniform constant speed { means his speed remains constant }

FORMULA:

Speed = Distance / time

           =  100/9.8

           =  10.2040 m/s

Given that we need to  convert m/s into km/hr,

So,

Speed = 10.2040 × 5/18

           =  51.02040/18

           =  2.83446666 so on

Speed ≅ 2.84 km/hr

Hence uniform speed at with athlete run is 2.84 km/hr

❆ Use the newtons 3 laws of motion according to given quantities and find the answers . They are,

❆ v = u + at  

❆ s = ut + 1/2 at²

❆ v² - u² = 2as

❆ Sn = u +  (2n -1) used to find time in nth seconds

❆ In case when distance and time are given use

❆ Speed = Distance / Time ❆

❆ With these formulas you can apply the given quantities and find the answers

To learn about this answer detailly refer,

brainly.in/question/16808022

Thanks for asking

Hope it helps