Question

The first 10 m of a 100 m dash are covered in 2 s by a sprinter who

Answer 1

Answer:

Calculate the sprinter's constant acceleration during the first 2 s:

$s= ut + \frac{1}{2} at^{2}$

Given that,

s = 10m

u = 0 m/s

t = 2s

$s= ut + \frac{1}{2} at^{2}\\ \frac{1}{2} at^{2}= s- ut\\a= \frac{2(s-ut)}{t^{2} } \\a= \frac{2(10-0)}{2^{2} }\\a = \frac{20}{4}\\ a = 5 m/s^{2}$

What is the sprinter's velocity after 2 s?

v = u + at

given,

t = 2s

a = 5 m/s²

u = 0 m/s

v = 0 + (5 × 2)

v = 10 m/s

- Calculate the total time required to run the full 100 m.

first 10m is completed by 2 seconds.

and it is stated that The remaining 90 m is run wit

same velocity the sprinter had after 2 s.

For the rest 90m,

s = vt

v= 10 m/s

t = ?

s = 90

t = 90 ÷ 10

t = 9s

total time : (2+9) = 11 seconds