Question

select the correct answer.
the velocity of a ball as it is thrown up is 20 meters/second. it attains zero velocity after 3.5 seconds. what is the average acceleration of the ball during its upward flight?
a. 5.7 meters/second
b. 0.57 meters/second
c. -0.57 meters/second$^2$
d. -5.7 meters/second$^2$
e. 5.5 meters/second$^2$

Explanation:

Step1: Recall average acceleration formula

Average acceleration is $\bar{a} = \frac{v_f - v_i}{t}$, where $v_f$ = final velocity, $v_i$ = initial velocity, $t$ = time.

Step2: Identify given values

$v_i = 20\ \text{m/s}$, $v_f = 0\ \text{m/s}$, $t = 3.5\ \text{s}$

Step3: Substitute values into formula

$\bar{a} = \frac{0 - 20}{3.5} = \frac{-20}{3.5} \approx -5.7\ \text{meters/second}^2$

Answer:

D. -5.7 meters/second²