The frequency of an x-ray wave is 3 Hz and its wave speed is 90 m/s. What is the x-rays wavelength?

How much heat is required to convert 0.3 kg of ice at 0°c to water at the same temperature

Abucket full of water weights 4 kg and water well is 10m deep. a girl draws water from the well. it takes the girl 3 minutes to draw a bucket full of water from the well. what is the power of the girl?

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?