Which one of the following types of electromagnetic radiation causes certain substances to fluoresce?
a. ultraviolet rays
b. infrared waves
c. x rays
d. cosmic rays

Akg a of 55 m at an of 11 ? . if is at 98 km/h,be ?

Apulley system is used to lift a 2,000 newton engine up a distance of 3 meters. the operator must apply a force of 250 newtons to the chain of the pulley system to lift the motor. to lift the engine 3 meters, the operator must pull a total of 30 meters of chain through the pulley system. what is the value of di?

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?