Aball whirls around in a vertical circle at the end of a string. the other end of the string is fixed at the center of the circle. assume that the total energy of the ball-earth system remains constant. (a) what is the tension in the string at the bottom? (use the following as necessary: m for mass of the ball, g for gravitational acceleration, vb for velocity at the bottom, and r for radius of the circle.) tb = incorrect: your answer is incorrect. (b) what is the tension in the string at the top? (use the following as necessary: m, g, vt for velocity at the top, and r.) tt = (c) how much greater is the tension at the bottom? (use the following as necessary: m, g.)

1. consider the case in which air fills air shocks on a truck trailer. the pressure in the shocks is 2 mpa. the temperature is 300 k. the diameter of the shock piston is 10 cm and the initial length of the cylindrical cavity containing the compressed air is 40 cm. a. the truck is gradually loaded over a period of a day in a static setting. the temperature is held constant for the atmosphere and thus for the gas shock. calculate the compressibility of the air in the shock for this condition when the truck is initially being loaded. b. if the shocks were loaded in a dynamic setting by driving over bumps, what would be the compressibility? state your assumption. c. what is the initial load on the shock if the shock is in an atmospheric 100 kpa? d. if the shock is compressed using the process described in part a, and the air shock compressed air cavity length decreases to 20 cm, what is the additional load applied to the shock?

Which of the following is the phase that results when the moon is on the opposite side of the earth from the sun? a. quarter moon b. crescent moon c. new moon d. full moon

Suppose that 27 j of work is needed to stretch a spring from its natural length of 6 m to a length of 9 m. (a) how much work is needed to stretch the spring from 12 m to 14 m? j (b) how far beyond its natural length will a force of 78 n keep the spring stretched?