Which of the following is a completely inelastic collision? Two balls collide, stick to each other, and move together after the
collision.

Two balls collide and move at a right angle to each other after the
collision.
A ball with velocity v collides with a ball at rest; after the collision the
first ball is at rest and the second ball has velocity v.
a ball rebounds against a wall, reversing its velocity.
Two balls collide head on, each reversing its velocity.

What is an aquifer for science class

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.

By examining a wave’s pattern after it interacts with a barrier or gap, measurements can be made to better understand certain wave phenomena. what is a broad question you can answer by doing this experiment?