89 740 Gl

About 3 weeks ago i was driving and as i went around a curve at about 50 my car started vibrating violently i hit my brakes and it stopped i got where i was going and it didnt make the noise again until yesterday i was driving and as i approched 60mph it did it again what kind of problem is this and what can i do about it

First check if it's just a 50-60 mph thing, if you get past 60 and it stops then there's a tire balancing in your future. If it just starts at 50 and continues then there's an alignment due. If you've had both of those recently then that might be an altogether different problem which requires further observation.