50 yards

In any case, despite their hulky features, bears in the wild are remarkably quick. Grizzlies can attain speeds of up to 35 mph (56 kph) across a distance of 50 yards (45.7 m). The grizzly can run 50 yards (45.7 m) in just three seconds, which is why you should never run from a bear!

Source: https://kidadl.com/facts/grizzly-bear-speed-interesting-facts-you-may-not-believe