The resistance of a conductor is proportional to its length. suppose that the lengths of the two samples were doubled. how would this affect their electrical resistance at 20 k?

a.) the resistance of both material a and material b would increase.
b.) the resistance of both material a and material b would not change.
c.) the resistance of material b would increase, but the resistance of material a would not change.
d.) the resistance of material a would increase, but the resistance of material b would not change.

Sally and sue were investigating the topic of friction in science. they used a small car and a ramp as seen in the picture to test what they were learning. they knew that they slipped easily on waxed floors but not on carpet, so they decided to change the material on the surface of the ramp to see what happened. they planned to use glass, carpet, aluminum foil, and sandpaper and run the car down the ramp over each surface. what would be the best research question to guide the girls' experiment? a) does the amount of surface area affect the friction on the moving car? b) will the car travel fastest on the glass surface? c) how does the angle of the ramp affect the speed of the car? d)do rougher surfaces tend to create more friction than smooth surfaces?

Me with biology endocrine system crossword also image left i need with hw

What is responsible for the uneven heating between the poles and the equator on any given day