What is a broken car strut?
A strut combines the function of a shock absorber with the ability to support sideways loads while supporting the vehicle.
This is why your ride is cushioned or fluid vs bouncy. When a strut goes bad it can completely disable the vehicle and cause damage to other parts of the chassis system. Most manufacturers recommend replacing the struts (or shocks) at 75,000 Miles or every 5 years. This repair should be done in pairs (both sides of the vehicle and is easily done in a day.
Below are pictures of a broken strut. Luckily this happened in a parking lot and not on a highway.