Given that:

= 2i + 9j ; and ⃗ = -i – 4j . Find . ⃗

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.

answer: cesare beccaria developed the classical school of criminology with from philosopher jeremy bentham

explanation:

fgravity=10x10=100n case 1

fgravity=30x20=600n case 2

6 times more

i think the answer is a, hope this : )