A rotating disc has a knob on the edge of it. The disk completes a rotation every 3 s. calculate the angular velocity of the knob. A. 7.3 rad/s B. 15.7 rad/s C. 18.8 rad/s D. 2.1 rad/s

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

The plum pudding model of the atom state that ?

What are the factors that affect the resistance of a wire?