Question

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

from rest and accelerates constantly. The remaining 90 m is run wit
same velocity the sprinter had after 2 s. In this context, answer the follo
questions.
Calculate the sprinter's constant acceleration during the first 2 s.
What is the sprinter's velocity after 2 s?
- Calculate the total time required to run the full 100 m.
1 Draw the displacement-time graph for the sprinter.
Classify the following situations as examples of balanced' and 'unbala
orces.
Two forces of 20 N acting towards left.
accelerating nlane​

Answer 1

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

`s= ut + (1)/(2) at^(2)`

Given that,

s = 10m

u = 0 m/s

t = 2s

`s= ut + (1)/(2) at^(2)\\ (1)/(2) at^(2)= s- ut\\a= (2(s-ut))/(t^(2) ) \\a= (2(10-0))/(2^(2) )\\a = (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