A runner makes one rap round 200m track in a time 25s, what is the average speed and velocity

Aray of light traveling parallel to the principal axis of a concave mirror will be reflected through the mirror's

Which statement correctly describes the relationship between frequency and wavelength?

Unpolarized light falls on two polarizer sheets whose transmission axes are at right angles. a third polarizer is placed between the first two so that its axis makes a 52-degree angle with the axis of the first polarizer. a) what fraction of the incident light intensity is transmitted through the first polaroid? b) what fraction of the incident light intensity is transmitted through the second polaroid? c) what is the angle of polarization of the light that enters the third polaroid? d) what fraction of the incident light intensity is transmitted through the third polaroid. e) what happens if the middle polaroid is removed?