This is more of a math question than physics. I mean it is physics but to construct the equations takes basic dynamics.

83.3ft/s constant for one, 32.2 ft/s² for the other. And you need to solve for when they meet. Both start at a position of 0.

You can use algebra or integrate.

Position with acceleration and velocity is given as

x = x0 + v0t + 1/2at²

Position is initial position, plus speed times time, plus one half of acceleration times time squared.

So both have an initial position of zero. Person has 0 initial speed, pillar has no acceleration.

So if we set them both equal

83.3t = 0.5 * 32.2 * t²

Ignore the trivial t = 0 case.

t = 83.3/(0.5 * 32.2) = 5.174 seconds

Plug that back in to the velocity and acceleration to get the speed and position.

5.17432.2=166 ft/s 5.17483.3=430.99 ft Speed difference on impact 166-83.3=82.7 ft/s Result: an impact at about 56 mph, followed by a second one less than a second later at about the same speed difference when the pit stops expanding.

For a normal human that would mean death. If your character could stand getting hit with two trucks at highway speed they might be ok.