Two students in a physics laboratory each have a concave mirror with the same radius of curvature, 45 cm. each student places an object in front of a mirror. the image in both mirrors is two and a half times the size of the object. however, when the students compare notes, they find that the object distances are not the same. what is the distance of the closer object?

Fill in the blank. the number of each type of element in the compound (other than 1) is represented by a small number to the right of the element symbol.

In the sport of parasailing, a person is attached to a rope being pulled by a boat while hanging from a parachute-like sail. a rider is towed at a constant speed by a rope that is at an angle of 15 ∘ from horizontal. the tension in the rope is 1900 n. the force of the sail on the rider is 30∘ from horizontal. what is the weight of the rider? express your answer with the appropriate units.

Which is not true about oxygen-17 and oxygen-18?