What two qauntities must be known to calculate the density of a sample of matter

Agymnast dismounts off the uneven bars in a tuck position with a radius of 0.3m (assume she is a solid sphere) and an angular velocity of 2rev/s. during the dismount she stretches out into the straight position, with a length of 1.5m, (assume she is a uniform rod through the center) for her landing. the gymnast has a mass of 50kg. what is her angular velocity in the straight position?

Wind and moving water provide energy. question 1 options: chemical mechanical thermal none of the above

Name three populations commonly found in a prairie system