Causal questions often begin with what word?

how

where

when

why

Two red blood cells each have a mass of 9.0 multiply.gif 10-14 kg and carry a negative charge spread uniformly over their surfaces. the repulsion arising from the excess charge prevents the cells from clumping together. one cell carries −2.50 pc of charge and the other −3.10 pc, and each cell can be modeled as a sphere 7.5 μm in diameter. (a) what speed would they need when very far away from each other to get close enough to just touch? assume that there is no viscous drag from any of the surrounding liquid. answer is: 321 m/s how do i find this (b) what is the maximum acceleration of the cells in part (a)? answer is: 1.38e+10 m/s2 how did they find this answer

An automobile of mass 2000 kg moving at 30 m/s is braked suddenly with a constant braking force of 10000 n. how far does the car travel before stopping?

1. a net force of 100 newton’s is applied to a wagon for 5 seconds. this causes the wagon to undergo a change in momentum of