As you are leaving a building, the door opens outward. if the hinges on the door are on your right, what is the direction of the angular velocity of the door as you open it?

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

When the force acting on an object points at least partially in the direction of the motion the work done is considered to be negative

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)