which of the following is not true about friction?
a. friction is an electricrstatic force between two surface.
b. friction does initiate motion, it does not responds to motion.
c. friction depends on the types of materials that are in contact.
d. friction depends how the net normal force pressing the two surfaces in contact.


7. in the top picture, Kent budget is pulling upon a rope that is attached to a wall. in the bottom picture, Kent is pulling upon the rope that is attached to an elephant. in each case, the force scale raeds 500 Newton. Kent is pulling...



a. with more force when the rope is attached to the wall.
b. with more force when the rope is attached to the elephant.
c. the same force in each case.
d. non of the above.


8. what is the acceleration of a 10 kg cart experiencing 150 N net force?
a. 15 m/s²
b. 10 m/s²
c. 1500 m/s²
d. 15 m/s²

9. when you brush your teeth, you exert force on the brush. which of the following will result as you do this?
a. the force of the brush is exerted on your hand.
b. the force of your teeth is exerted on the brush.
c. the force of the brush is exerted on your teeth.
d. the force of your teeth is exerted on your hand.

10. why do objects fall to the ground?
a. they are pulled by the air.
b. they are pulled by the earth.
c. they are pulled by the moon.
d. they go back to their natural place. ​