How do i find R (radius) and the angle

How do you tell if someone actually cares about you? and just say they do?

How to tell if a molecule is polar or nonpolar with electronegativity

Aball with a mass of 275 g is dropped from rest, hits the floor and rebounds upward. if the ball hits the floor with a speed of 2.40 m/s and rebounds with a speed of 1.70 m/s, determine the following. (a) magnitude of the change in the ball's momentum (let up be in the positive direction.)