Question

a ball is thrown up in the air with an initial velocity of 40 m/s. what is the balls velocity after 2 seconds? (use g = 10m/s²)
20 m/s traveling upward
20 m/s traveling downward
0 m/s
40 m/s traveling downward

Explanation:

Step1: Identify the kinematic - equation

We use the equation $v = v_0+at$. Here, $v_0$ is the initial velocity, $a$ is the acceleration, and $t$ is the time. The acceleration due to gravity $g$ acts downwards, so $a=-g=- 10m/s^{2}$, $v_0 = 40m/s$, and $t = 2s$.

Step2: Substitute the values

Substitute the values into the equation $v=v_0 + at$. So $v=40+( - 10)\times2$.

Step3: Calculate the result

First, calculate $( - 10)\times2=-20$. Then $v = 40-20=20m/s$. Since the result is positive, the direction is upward.

Answer:

A. 20 m/s traveling upward