In a physics lab experiment, one end of a horizontal spring that obeys Hookes law is attached to a wall. The spring is compressed 0.400 m, and a block with mass 0.300 kg is attached to it. The spring is then released, and the block moves along a horizontal surface. Electronic sensors measure the speed v of the block after it has traveled a distance d from its initial position against the compressed spring. The measured values are listed in the table. (a) The data show that the speed v of the block increases and then decreases as the spring returns to its unstretched length. Explain why this happens, in terms of the work done on the block by the forces that act on it. (b) Use the workenergy theorem to derive an expression for v2 in terms of d. (c) Use a computer graphing program (for example, Excel or Matlab) to graph the data as v2 (vertical axis) versus d (horizontal axis). The equation that you derived in part (b) should show that v2 is a quadratic function of d, so, in your graph, fit the data by a second-order polynomial (quadratic) and have the graphing program display the equation for this trendline. Use that equation to find the blocks maximum speed v and the value of d at which this speed occurs. (d) By comparing the equation from the graphing program to the formula you derived in part (b), calculate the force constant k for the spring and the coefficient of kinetic friction for the friction force that the surface exerts on the block.
One more entropy problem: o Two boxes, of unequal size, have different amounts of energy. The box on the left has two packets of energy, and can contain 9. The one on the right has 3 packets and can contain 6 o If one packet of energy moves from the 6 to the 9, what is the change in entropy for : o • The 9box o • The 6box o • The system as a whole If, after one packet is moved from 6 9, another is moved (so that now the 6box has only one packet), what is the change in entropy for: o • The 9box o • The 6box o • The system as a whole o What is the most likely final state Will you see this state every time How do the temper