1.) ball bearings are placed between skateboard wheels and other moving parts because a) static friction is easier to overcome than sliding friction b) fluid friction is easier to overcome than rolling friction c) rolling friction is easier to overcome than sliding friction d) sliding friction is easier to overcome than rolling friction

the correct choice is

C) rolling friction is easier to overcome than sliding friction

sliding friction acts when two surfaces are in contact with each and they slide over each other. rolling friction acts when one surface rolls over the other surface. in this situation , are in contact is small  and circular which makes the rolling friction smaller as compared to the sliding friction.

! 55 !  

write a paragraph or story to explain the transformation between potential and kinetic energy as shown in your picture or model.  

you should have at least 5 complete sentences with a main idea and supporting details.  

you must include the following words:  

potential energy

kinetic energy

mechanical energy

conservation of energy

dude, this is hard lol : ))

the word that best describes martin luther king jr.'s tone in the video is dignified

martin luther king, jr. was a social activist and baptist minister who played a key role in the american civil rights movement from the mid-1950s until his assassination in 1968. the video shows his manner and attitude having or showing a composed or serious manner that is worthy of respect so dignified is the correct answer