A child and sled with a combined mass of 53.8 kg slide down a frictionless hill that is 11.5 m high at an angle of 25° from horizontal. The acceleration of gravity is 9.81 m/s. If the sled starts from rest, what is its speed at the bottom of the hill?

Radioisotopes often emit alpha particles, beta particles, or gamma rays. the distance they travel through matter increases in order from alpha to gamma. each radioisotope has a characteristic half-life, which is the time needed for half of a sample of radioisotope to undergo nuclear decay. which quality is desirable for a radioisotope that is used for medical imaging of a specific organ? check all that apply. half-life of several years half-life of several days half-life of several seconds emission of gamma rays emission of alpha particles ability to be attached to a compound used by the body ability to pass through the body without being absorbed