in the particle under constant acceleration model we identify the variables and parameters Vxi, Vxf, ax, t, and xf-xi. Of the equations in the model, Equations 2.13-2.17, the first does not involve xf-x, the second and third do not contain ax, the fourth omits Vxf, and the last leaves out t. So, to complete the set, there should be an equation not involving Vxi. Derive it from the others.

The heater element of a 120 v toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. the resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ω·m. the toaster is operated at a voltage of 120 v. (a) what is the power drawn by the toaster? (b) if the cost of electricity is 12 ¢ per kilowatt-hour, and it takes 2 minutes to toast bread, how much does it cost for toasted bread? (c) when the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to it’s resistivity when at operating temperature? explain.