Help please if u don’t know one don’t answer it but do the most that u can

Give an example in which the electrical energy changes to light energy

What kind of simple machine is a catapult?

An important dimensionless parameter concerned with very high-speed flow is the mach number, defined as v/c, where v is the speed of the object such as an airplane or projectile, and c is the speed of sound in the fluid surrounding the object. for a projectile traveling at 1170 mph through air at 50 ˚f and standard atmospheric pressure, what is the value of the mach number?