Help identifying inverted wedge with studs on the slope
It's an old piece from 1969 - 1982, typically used for train cars or trucks with buckets that could be tipped to dump their contents.

3145 Vehicle, Tipper End Flat with Pins



There's also a newer variant from 1996 - 2016 without the pins and hole.

30022 Vehicle, Tipper End Flat without Pins