Question

a sprinter explodes out of the starting block with an acceleration of +2.05 m/s², which she sustains for 1.33 s. then, her acceleration drops to zero for the rest of the race. what is her velocity at (a)t = 1.33 s and (b) at the end of the race? (a) number units (b) number units attempts: 0 of 3 used submit answer save for later

Explanation:

Step1: Recall velocity - time formula

The formula for velocity $v = v_0+at$, where $v_0 = 0$ (starts from rest), $a$ is acceleration and $t$ is time.

Step2: Calculate velocity at $t = 1.33s$

Given $a = 2.05m/s^{2}$ and $t = 1.33s$, $v=0 + 2.05\times1.33$.
$v=2.05\times1.33 = 2.7265m/s$.

Step3: Analyze velocity at the end of the race

After $t = 1.33s$, acceleration $a = 0$. When $a = 0$, the velocity remains constant. So the velocity at the end of the race is the same as the velocity at $t = 1.33s$.

Answer:

(a) Number: $2.73$ (rounded to two - decimal places), Units: $m/s$
(b) Number: $2.73$ (rounded to two - decimal places), Units: $m/s$