A world class sprinter is travelling with speed 12.0 m/s at the end of a 100 meter race. Suppose he decelerates at the rate of 2.00 m/s^2. (a) How long does it take him to come to a stop? (b) How far does he travel as he is stopping?

after 6 second it will stop

he travel 36 m to stop

Explanation:

given data

speed = 12 m/s

distance = 100 m

decelerates rate = 2.00 m/s²

so acceleration a = - 2.00 m/s²

to find out

how long does it take to stop and how far does he travel

solution

we will apply here first equation of motion that is

v = u + at ... 1

here u is speed 12 and v is 0 because we stop finally

put here all value in equation 1

0 = 12 + (-2) t

t = 6 s

so after 6 second it will stop

and

for distance we apply equation of motion

v²-u² = 2*a*s ... 2

here v is 0 u is 12 and a is - 2 and find distance s

put all value in equation 2

0-12² = 2 * (-2) * s

s = 36 m

so he travel 36 m to stop