Straightforward but needs energy concepts) an electron is traveling with initial ki- netic energy k in a uniform electric field. the electron comes to rest momentarily after traveling a distance d. find an expression for the magnitude of the electric field in terms of q, d and k. what is the direction of the electric field? 3. (intermediate. fairly involved) two parallel, metal plates with separation distance de 1.00 cm carry charges of equal magnitude but opposite sign. the plates are oriented hori. zontally. assume the electric field between the plates is uniform, and it has a magnitude of 2,140 n/c. a charged particle with mass 2.00 x 10-16 kg and charge 1.07 x 10- cis projected from the center of the bottom negative plate with an initial speed of 1.04 x 10 m/s at an angle of 37.0° above the horizontal. assume the plates are square with side length=20.0 cm. make a sketch of the problem and answer the following. a) describe the trajectory of the particle. b) which plate does it strike? c) where does it strike, relative to its starting point? i. e., the horizontal distance from the initial position.

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?

While studying chemical reactions and conservation of matter, sarah's class conducted a variety of experiments. sarah and her lab partner found the mass of a wax candle and placed the candle in a flask. the students lit the candle and let it burn to completion. all that was left was wax and charred candle wick. per their teacher's instructions, the students found the mass of the products. their data can be seen in the data table. formulate a hypothesis the students could test to explain why the experiment did not support the law of conservation of matter. a) the students could repeat the experiment using different candles; there might have been a flaw in the candle. b) the experiment should be repeatable. the students should run several trials and then take an average of the after mass in each trial. c) the students should have someone in the class check their measurement skills as they repeat the experiment. they may have made an error using the balance. d) the students should burn the candle in a container that has some type of lid so that any gas that is a product of the reaction can be contained and massed. submit

In a heat engine if 1000 j of heat enters the system and the piston does 500j of work, what is the final internal energy of the system if the inital energy was 2000 j1.write the equation2.list out your known variables 3. plug the numbers into the equations4.solve 5.write your solution statement that includes initial energy and final energy added.