Answer:
Explanation:
initial velocity u = 0
final velocity v = 11.3 m /s
distance covered s = 12.8 m
v² = u² + 2 a s
11.3² = 0 + 2 x a x 12.8
a = 4.99 m /s²
again ,
v = u + a t
11.3 = 0 + 4.99 t
t = 2.26 s .
Rest of the sprint will be covered with uniform velocity .
Distance covered = 100 - 12.8 = 87.2 m
speed = 11.3 m /s
time taken = 87.2 / 11.3 = 7.7 s
Total time of 100 m sprint = 7.7 + 2.26 = 9.96 m .
b )
Let the time taken to reach the top speed be t .
acceleration a = 11.3 / t
distance covered s = 1/2 a t²
= .5 x (11.3 / t) x t²
= 5.65 t
Rest of the distance = 100 - 5.65 t
time taken to cover rest of the distance = (100 - 5.65 t ) / 11.3
Total time = (100 - 5.65 t / 11.3 ) + t = 9.75
100 - 5.65 t + 11.3 t = 11.3 x 9.75
100 + 5.65 t = 110.175
5.65 t = 10.175
t = 1.8
acceleration a = 11.3 / t
= 11.3 / 1.8
= 6.278 m /s²
distance covered in 1.8 s
s = 1/2 a t²
= .5 x 6.278 x 1.8²
= 10.17 m .
