Rhea kicks a soccer ball at 13 km/h to sean. after kicking the ball, the speed of the soccer ball from rhea’s reference frame is 13 km/h. the speed of the soccer ball from sean’s reference frame is 22 km/h.
which conclusion is best supported by the information?
a. rhea is standing still after kicking the ball, and sean is running.
b. sean is standing still, and rhea is running while kicking the ball.
c. both soccer players are standing still after the ball is kicked.
d. both soccer players are running while the ball is in motion.

Researchers determine that the biodiversity in a woodland region is declining. they identify two major threats to the region's biodiversity, a method to address each threat, and the expected outcome of each method. this information is shown in the table. a) reforestation would not benefit many species because most forest species live on the ground. b) reforestation would take the longest time to be effective because trees take several years to grow. c) biological augmentation would benefit only a few species because is is typically not very effective. d) biological augmentation would take less time to ve effective because it targets the majority of prey species.

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)