Suppose that a 110 kg football player running at 7.5 m/s catches a 0.47 kg ball moving at a speed of 23.5 m/s with his feet off the ground, while both of them are moving horizontally. Final speed = 7.44 m/s
Calculate the change in kinetic energy of the system, in joules, in this case.

Unpolarized light of intensity i_0=750w/m^2 is incident upon two polarizers. after passing through both polarizers the intensity is i_2=280w/m^2. (a) what is the intensity of the light after it passes through the first polarizer in w/m^2? (b) write an equation for the angle between the polarizers in terms of the initial (i_0) and final (i_2) intensities. (c) find the angle between the polarizers in degrees.

The energy of a photon was found to be 3.38 × 10–19 j. planck’s constant is 6.63 × 10–34 j • s. which color of light corresponds to this photon?

If an athlete runs once around a track, back to the starting line, her average velocity is zero. true or false?