A girl and boy are moving a wagon full of books across the floor at a constant speed. We know the girls pulling the wagon at an angle of 36.9°. She is pulling with a force of 50 N and a boy is pushing with a force of 30N.  The mass of the Wagon and books together is 90 KG. Determine the force of gravity acting on the circled object, the normal force acting on the circled object, and the force of friction.

What would the difference of spectral lines emitted by hydrogen gas in distant galaxies which is normally found at a wavelength of 21 cm on earth, be observed at 21.1 centimeters?

What should the power status of a circuit be when measuring resistance with an ohmmeter?

Acylinder with a movable piston contains 11.7 moles of a monatomic ideal gas at a pressure of 1.32×10^5 pa. the gas is initially at a temperature of 300 k. an electric heater adds 43200 j of energy into the gas while the piston moves in such a way that the pressure remains constant. cp=20.79 j k^−1 mol^−1 for a monatomic ideal gas, and that the number of gas molecules is equal to avogadro's number (6.022×10^23) times the number of moles of the gas. (a) what is the temperature of the gas after the energy is added? (b) what is the change in volume of the gas? (c) how much work is done by the gas during this process?