There is some good news and some bad news in finding V. As your object is plummeting in air, you cannot use the V = sqrt(2gH) equation, which applies only in a vacuum. That's the bad news. The good news is that terminal velocity for just about everything hovers around 120 mph or 176 ft/sec.
So now you have F = m dV/dT = (3/32)*176/dT; where you must guesstimate the impact interval, which is the time the object takes to go from V to zero upon impact. You can make an educated WAG on what that might be, but the best thing to do here is guess a range of likely values based on the surface material the object will crash into.
First, experience dictates that dT < 1.0 second. When things hit the ground, they hit with a thud. And that's a short period. So plug in, say, .1, .4, .7, and 1.0 seconds to see the range of possible forces. That gives 165.00, 41.25, 23.57, 16.50 pounds of force from the change in momentum But, this is important, you need to add the weight 3 lb to each of these values for the total force upon impact.
Note that terminal velocity, 120 mph, is reached rather quickly; so it would apply to just about any height above 5000 ft. And below a height where terminal velocity is not reached, the impact speed will be slower than that nominal 120 mph.