calculate the mass of a bus if it produces a force of 20,000N while accelerating at a rate of 8m/s-2

Force=mass × acceleration.

20,000=mass × 8.

20000=8m.

m=20000/8.

=2500g

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.

this could be newton#'s law of cooling. the cooling curve is exponential