Two billiard balls, each with a mass of 0.35 kg, strike each other head-on. one ball is initially moving left at 4.1 m/s and ends up moving right at 3.5 m/s. the second ball is initially moving to the right at 3.5 m/s. find the velocity of the second ball.

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. you see that the patch of light seems to be a circular diffraction pattern. it appears that the central maximum is about 1 cm across and you estimate that the distance from the window shade to the wall is about 3 m. what is (a) the average wavelength of sunlight? (b) the diameter of the pinhole?

Why is rain likely when warm, moisture-laden air meets cold air? a) the lighter warm air will rise and cool down, causing condensation and rain. b) the cold air moves faster and pushes the warm air away, causing condensation and rain. c) the moisture in the warm air condenses on contact with the cold air, causing rain to fall. d) the cold air mixes with the warm air, reducing its temperature causing moisture to condense.

The radius of an atom is closest in size to a