A simplified model of a bungee jump can be analyzed in two sections: a freefall section in which the bungee cord has not yet begun stretching and a section in the lower portion of the jump in which the bungee cord stretches and exerts a force on the jumper. The cord is assumed to exert zero force on the jumper until its length exceeds its maximum unstretched length. Determine the maximum unstretched length of a bungee cord of spring constant 100 N/m such that a 70-kg jumper will not hit the ground when jumping from a height of 45 m.

Acylinder with a movable piston contains 11.7 moles of a monatomic ideal gas at a pressure of 1.32×10^5 pa. the gas is initially at a temperature of 300 k. an electric heater adds 43200 j of energy into the gas while the piston moves in such a way that the pressure remains constant. cp=20.79 j k^−1 mol^−1 for a monatomic ideal gas, and that the number of gas molecules is equal to avogadro's number (6.022×10^23) times the number of moles of the gas. (a) what is the temperature of the gas after the energy is added? (b) what is the change in volume of the gas? (c) how much work is done by the gas during this process?

One form of energy can be another type of energy. a. created to form b. transformed into c. destroyed and then created to form

Two 1.20-m nonconducting wires meet at a right angle. one segment carries + 2.50 µc of charge distributed uniformly along its length, and the other carries - 2.50 µc distributed uniformly along it, as shown in fig. 21.50. ( a. find the magnitude and direction of the electric field these wires produce at point p, which is 60.0 cm from each wire. ( b. if an electron is released at p, what are the magnitude and direction of the net force that these wires exert on it?