The model below shows an atom of an element. 10 light gray and 8 dark gray balls sit at the center with 2 concentric black rings around them. The inner ring has 2 medium gray balls on it, and the outer ring has 6 medium gray balls on it. At bottom, a dark gray ball = +1, a light gray ball = 0, a medium gray ball = negative 1.

What is the atomic number of this atom?

6
8
9
16

In an experiment, how can i change human errors? be specific.

Emmy kicks a soccer ball up at an angle of 45° over a level field. she watches the ball's trajectory and notices that it lands, two seconds after being kicked, about 20 m away to the north. assume that air resistance is negligible, and plot the horizontal and vertical components of the ball's velocity as a function of time. consider only the time that the ball is in the air, after being kicked but before landing. take "north" and "up" as the positive ‑ and ‑directions, respectively, and use ≈10 m/s2 for the downward acceleration due to gravity.

Aplayer uses a hockey stick to push a puck at a constant velocity across the ice. the weight of the puck is 170 n. the coefficient of friction is 0.0600. with what force must the player push the puck so that his force just equals the frictional force? 28.3 n 0.999 n 0.102 n 0.0104 n