A pulley system has an efficiency of 74.2%. If you perform 200 J of work, how much useful work does the pulley perform?
A. 52 J
B. 113 J
C. 148 J
D. 200 J
SUBMI

Amira pulls a 3 pound wagon 4 feet. how much work has she done?

3. a lunar exploration vehicle was created by a research team. it weighs 3,000 kg on the earth. it needs an acceleration of 10 m/s2 on the moon. in order to have the same acceleration, what will be the net force acting on the vehicle on the earth?

Ultraviolet radiation is dangerous because it has a high enough energy to damage skin cells. what is the best explanation of the relationship between wavelength and wave energy? a) wave energy is related only to frequency, not wavelength. b) longer wavelengths have lower frequencies but higher energy. c) the shorter the wavelength, the lower the frequency and the higher the energy. d) the shorter the wavelength, the higher the frequency and the higher the energy.