The vx2 in the equation for average pressure in part c. should more properly be designated as the average of the square of the x-components of the velocities vx2 The N particles inside the container move at different speeds and in different directions. How is vx2 related to the average of the square of the speeds v2. Hint: Assume that one-third of the particles move in each of the three directions (x, y,z), and ask yourself if there is any reason the average would be different in different directions.

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.

myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.