What is the wave speed of a 6 m wave with a frequency of 20 Hz?

Gunpowder residue is most likely to show up where on a shooters hands

What do you think car designers do if the damage caused by a crash test is too severe?

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?