Radar guns are used to measure the speed of moving objects. Radar guns work by projecting radio waves of known frequencies onto moving objects.

How is a radar gun able to calculate the speed of a moving object using radio waves?

A.

Radio waves are reflected off of the moving object, which causes a change in frequency that can be analyzed by the software of the radar gun to calculate the object's speed.

B.

Radio waves are diffracted by the moving object, which causes a change in wave speed that can be analyzed by the software of the radar gun to calculate the object's speed.

C.

Radio waves are refracted by the moving object, and the angle of refraction of the waves can be analyzed by the software of the radar gun to calculate the object's speed.

D.

Radio waves are absorbed by the moving object, which causes an increase in the temperature of the object that can be analyzed by the software of the radar gun to calculate the object's speed

Organelles are 1. responsible for producing power for the cell 2. tiny structures in the cell that carry out the cell's activities 3. responsible for digestion in the cell 4. found outside of the membrane

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?

Light traveling in water, nwater = 1.33, strikes a plastic block at an angle of incidence of 51.4°; part of the beam is reflected and part is refracted. if the index of refraction of the plastic is 2.0, what is the angle made by the reflected and refracted beams?