Question

question 24 (problem reference 2 - 1) a tennis ball is shot vertically upward with an initial speed of 20.0 m/s. how long does it take the tennis ball to reach its maximum height? 6.08 s 0.50 s 4.08 s 2.04 s 9.80 s

Explanation:

Step1: Identify the kinematic - equation

We use the equation $v = v_0+at$. At the maximum - height, the final velocity $v = 0$. The acceleration $a=-g=- 9.8\ m/s^{2}$ (negative because it acts in the opposite direction of motion) and the initial velocity $v_0 = 20.0\ m/s$.

Step2: Solve for time $t$

From $v = v_0+at$, we can re - arrange it to $t=\frac{v - v_0}{a}$. Substituting $v = 0$, $v_0 = 20.0\ m/s$ and $a=-9.8\ m/s^{2}$, we get $t=\frac{0 - 20.0}{-9.8}=\frac{20.0}{9.8}\approx2.04\ s$.

Answer:

D. 2.04 s