4. Two objects are being lifted by a machine. One object has a mass of 2 kg, and is lifted at a speed of 2 ms. The other has a mass of 4 kg and is lifted at a rate of 3 ms.
a. Which object has more kinetic energy whule it is being lifted?
b. What does this tell you about the variable(s) that impact kinetic energy?
c. Which object had more potential energy when it was lifted a distance of 10 m?
d What does this tell you about the variable(s) that impact gravitational potential energy?

Imagine you had to physically add electrons, one at a time, to a previously neutral conductor. you add one electron very easily, but the second electron requires more work. in your initial post to the discussion, explain why this is. also, what happens to the work needed to add the third, fourth, fifth, and subsequent electrons

Determine the maximum r-value of the polar equation r =3+3 cos 0

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?