From BBC:
A Tyrannosaurus rex would have had great difficulty getting its jaws on fast, agile prey, a study confirms.
A US team has used detailed computer models to work out the weight of a typical “king of the dinosaurs”, and determine how it ran and turned.
The results indicate a 6 to 8-tonne T. rex was unlikely to have topped 40km/h (25mph) and would take a couple of seconds to swivel 45 degrees.
Slowcoach dino
The team’s computer modelling system estimated the centre of mass position and the inertia (resistance to turning), which have ramifications for how T. rex would have stood and moved and what it would have looked like.
As well as predicting the dinosaur’s likely body mass and top speed (25-40km/h or 15-25mph), the computer calculations gave the team an idea of the turning ability of a T. rex. This has never been done before.
More here.