Answer:
Matter can change state when thermal energy is transferred into or out of the substance. Ice melts and liquid water boils as thermal energy is added. Water vapor condenses and liquid water freezes as thermal energy is removed.
Friction is helpful:
- We use it to brake for cars
- We use it to fly planes
-We wouldn't be able to turn a door knob without friction ( Our hand would just slide off it)
Friction harmful:
-Our cars would get much better gas mileage without tire and air friction
- There would be no skinned knees if friction didn't exist (Like when your skating or football)
- We could do some pretty cool dance moves without friction
- Our shoes would last longer without friction
Answer:
Decreases
Explanation:
Hope this helps:) Good luck!
