1. the average kinetic energy of a molecule, is called thermal energy, it is directly related to absolute temperature. ke (average per molecule) = 12 m v2(average) = 32 kbt (kb =1.38×10−23 j/k) 2. the average speed of molecules in a gas: vrms = 3kbtm√ where vrms stands for root-mean-square (rms) speed. 3. the internal energy of a gas is the total energy of all the n atoms and molecules. for a monatomic gas, each atom (molecule) has only the kinetic energy. therefore, internal energy u = n ke (average per molecule) =n ( 32 kbt) = 32 nkbt = 32 nrt use the ideal gas law: pv = nkbt = nrt, then internal energy u = 32 pv (a) what is the average kinetic energy of a gas molecule at 17 °c? report result in 10-23 j. for example, if the result is 736*10-23 j, enter 736.

An insurance company wants to know if the average speed at which men drive cars is higher than that of women drivers. the company took a random sample of 27 cars driven by men on a highway and found the mean speed to be 72 miles per hour with a standard deviation of 2.2 miles per hour. another sample of 18 cars driven by women on the same highway gave a mean speed of 68 miles per hour with a standard deviation of 2.5 miles per hour. assume that the speeds at which all men and all women drive cars on this highway are both approximately normally distributed with unknown and unequal population standard deviations.

Athin plate moves between two parallel, horizontal, stationary flat surfaces at a constant velocity of v = 7.5 m/s. the two stationary surfaces are spaced 4 cm apart, and the medium between them is filled with oil whose viscosity is 0.9 n·s/m2. the part of the plate immersed in oil at any given time is 2 m long and 0.5 m wide. if the plate moves through the mid-plane between the surfaces, determine the force required to maintain this motion. what would your response be if the plate was 1 cm from the bottom surface (h2) and 3 cm from the top surface (h1)? if the plate moves through the mid-plane between the surfaces, the force required to maintain the motion will be n. if the plate was 1 cm from the bottom surface (h2) and 3 cm from the top (h1) surface, the force required to maintain the motion would be n.

An athlete swings a ball, connected to the end of a chain, in a horizontal circle. the athlete is able to rotate the ball at the rate of 8.13 rev/s when the length of the chain is 0.600 m. when he increases the length to 0.900 m, he is able to rotate the ball only 6.04 rev/s. (a) which rate of rotation gives the greater speed for the ball? 6.04 rev/s 8.13 rev/s (b) what is the centripetal acceleration of the ball at 8.13 rev/s? m/s2 (c) what is the centripetal acceleration at 6.04 rev/s? m/s2