Answer: 40m
Explanation: Distance is a function of speed/ velocity and time.
From the question the velocity along the z axis is given as 20 m/s at t = 0 secs We were ask to calculate the distance travelled when t = 2secs.
Recall that,
Velocity = distance travelled / time
Since we're calculating for distance we make it subject of formula;
Distance travelled = velocity * time
= 20m/s * 2s
= 40meter.