Pelicans tuck their wings and free-fall straight down whei} diving for fish. suppose a pelican starts its dive from q height of 16.0m and cannot change its path once committed. if it takes a fish 0.20 s to perform evasive action, at what minimum height must it spot the pelican to escape? assume the fish is at the surface of the water.

Cyclotrons are widely used in nuclear medicine for producing short-lived radioactive isotopes. these cyclotrons typically accelerate h- (the hydride ion, which has one proton and two electrons) to an energy of 5 mev to 20 mev. this ion has a mass very close to that of a proton because the electron mass is negligible—about 1 2000 of the proton’s mass. a typical magnetic field in such cyclotrons is 1.9 t. (a) what is the speed of a 5.0-mev h-? (b) if the h- has energy 5.0 mev and b = 1.9 t, what is the radius of this ion’s circular orbit?