U = 0, the initial vertical velocity
Ignoring air resistance, with g set to 9.8 m/s².
The duration, t, required for the pen to reach a vertical speed of 19.62 m/s can be calculated with
19.62 m/s = 0 + (9.8 m/s²)*(t s)
t = 19.62/9.8 = 2.00 s
Result: 2.0 s
According to Newton's first law, an object remains at rest until an external force acts upon it, or an object in motion continues to move at a constant speed without accelerating.
Thus, x can solely represent a body coming to a halt. Accordingly, the last option is the most correct.
