Hi,
Impact planes are like floors and walls. It is not very common for these things to move, so there is no reason to apply forces or any other loads to them.
Instead, you need to
- create a part using brick elements
- define contact between the plate and the head
- apply the force to the plate.
Ideally, you would make the plane from 1 brick element, which means creating that by hand. It should not be too hard.
Out of curiosity, what is the real world case where you have a known force moving a plate with a known mass and impacting the head? Or is it not an impact but a plate squeezing against the head? Ouch!