Why is a convex lens good for starting fires

The equation that describes a transverse wave on a string is y = (0.0120 m)sin[(927 rad/s)t - (3.00 rad/m)x] where y is the displacement of a string particle and x is the position of the particle on the string. the wave is traveling in the +x direction. what is the speed v of the wave?

Describe the function of the endomembrane system? what organelles are involved?

The charge on a charged sphere is: a)concentrated at its centerb)distributed uniformly throughout its volumec)clustered on its centerd)distributed uniformly over its surface