It might dangerous to raise an umbrella in a storm

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?

What is the temperature in degrees celsius of a substance with a tempature of 49k

Which accurately compares concave and convex lenses?