A hoop with mass m and radius R is rolling without slipping on a horizontal surface with its center moving at a speed v. The rotational inertia of the hoop about its center is mR2. What is its total kinetic energy

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?

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?

If the new moon happens on january 15th, what shape will it be on february 6th?