Santa Claus is dragging a 50 kg bag of toys across the flat roof of a house. The coefficient of friction between the bag and the roof is 0.45. What minimum force does Santa need to apply to get the bag moving?

Henry, whose mass is 95 kg, stands on a bathroom scale in an elevator. the scale reads 830 n for the first 2.4 s after the elevator starts moving, then 930 n for the next 2.4 s. part a what is the elevator's speed 4.8 s after starting? express your answer with the appropriate units.

While standing outdoors one evening, you are exposed to the following four types of electromagnetic radiation: yellow light from a sodium street lamp, radio waves from an am radio station, radio waves from an fm radio station, and microwaves from an antenna of a communications system. rank these type of waves in terms of increasing photon energy.

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