A horizontal force, F1 = 75 N, and a force, F2 = 18.3 N acting at an angle of θ to the horizontal, are applied to a block of mass m = 2.4 kg. The coefficient of kinetic friction between the block and the surface is μk = 0.2. The block is moving to the right.

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.

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.