Mary hikes 5 km north, then turns and hikes 2 km west, then turns south and hikes 4 km. What is her displacement? Remember to give magnitude (how far) and direction
(what angle and in what direction). Type your answer in the blank.

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

What is a neurotransmitter involved in mood reward, addiction, and motor behaviors?

The speed of sound in ice, water, and steam is shown. what best explains the speed of sound in different states of matter? sound travels fastest in ice because energy is easier to transfer when the molecules are close together. sound travels slowest in steam because the sound has to move around the gas molecules that are far apart. sound travels fastest in ice because the temperature of solids is always greater, so the heat transfers the sound energy. sound travels slowest in steam because the pressure is so great the sound cannot travel though the steam particles.