(a) for an ideal plane electromagnetic wave in vacuum, show that the energy crossing an area a in 1 second, with a normal to the direction of propaga- tion, is equal to the total field energy within a cylinder with base a and height 3 x 108 m. (b) show that cuav and explain this result in terms of conservation of energy.

An engineer designs a roller coaster so that a car travels horizontally for 162 ft, then climbs 127 ft at an angle of 31.0° above the horizontal. it then moves 127 ft at an angle of 46.0° below the horizontal. if we take the initial horizontal motion of the car to be along the +x-axis, what is the car's displacement? (give the magnitude of your answer, in ft, to at least four significant figures and give the direction of your answer in degrees counterclockwise from the +x-axis.)

What is the momentum of a 2 kg object moving at 15 meters per second

In the first law of thermodynamics, triangle e=q-w, what does q stand for