12. If a ball is dropped from rest and falls 8m to the ground, what is the speed just before it hits the ground? Take acceleration due to gravity to be 10m/s/s).
13. What acceleration would be needed by a car speeding up from 10m/s to 15m/s in 80m?

An object is 10 cm from the mirror, its height is 1 cm and the focal length is 5 cm. what is the image height? (indicate the object orientation by including the + or - sign with the answer.) hi = cm +1 -1 +10 -10

The coulomb's law explains which of the following? select all the force between two charged objects is inversely proportional to the charge on each object. the force between two charged objects is directly proportional to the charge on each object. the force between two charged objects is directly proportional to the distance separating them. the force between two charged objects is inversely proportional to the square of the distance separat coulomb's law is similar to newton's 2nd law. if the force between two objects is f and the charge on both objects is doubled, the new force between the would now be 2f. if the force between two objects is 2f and the distance separating them is doubled, the new force between the objects would now o the be zf.

Which statement correctly describes the interaction between magnetic poles? north and south poles attract each other. north and south poles repel each other. two north poles will attract each other. two south poles will attract each other.