Aworld-class sprinter can reach a top speed of about 11.5 m/s in the first 18.0 m of a race. what is the average acceleration of this sprinter and how long does it take him/her to reach that speed?

Answer

a = 3.674 m / s ^ 2

t = 3.13 s

Using the kinematic equations for the movement we have:

(1)

(2)

Where:

= initial position

= initial velocity

a = acceleration

t = time in seconds

= final speed

We know:

h = 18 m

  So:

 From (2) we have that:

From (1) we have to:

Then we clear "a" to find the acceleration.

Then, the time it takes to reach this speed is:

i think it’s a. this is because if they measured the mass of something with a mass of 150g, then their final answer would have to be approximately 150g. though all of their answers are almost 150, rosa and tran have the closest answers (or the exact answer) to the accurate one.

50 inches should be the resultant vector