You and your lab partner are asked to determine the density of an aluminum bar. the mass is known accurately (to four significant figures). you use a simple metric ruler to determine its size and calculate the results in
a. your partner uses a precision micrometer and obtains the results in
b. method a (g/cm3 ) method b (g/cm3 ) 2.2 2.703 2.3 2.701 2.7 2.705 2.4 5.811 the accepted density of aluminum is 2.702g/cm3 .
a. calculate the average density for each method. should all the experimental results be included in your calculations? if not, justify and omissions.
b. calculate the percent error for each methodâs average value.
c. which methodâs average value is more precise? which method is more accurate?

State the right hand rule of the direction of magnetic field in a conductor carrying current

Aroll in a paper machine is powered by a separately excited dc machine. operating point 1 (under load): the roll typically operates at 764 rpm and must provide 301 nm of torque to oppose the load of the paper. the armature voltage is 230v for this operating point operating point 2 (no load): when the load is removed the speed of the roll increases to 900 rpm (the field characteristics are unchanged) la ea dev m (a) calculate the maximum torque (units of nm) that the motor can supply with this applied voltage (b) calculate the value of the armature resistance, ra (in ohms) (c) at operating point 1 (loaded condition), the field current, i, and the total input power (armature field), are measured to be to be 10 a and 28,600 w respectively. use this information to calculate the value of the field resistance, rf (in ohms). (d) (d) at operating point 1 (loaded condition), calculate the motor efficiency. express your answer as a percent to at least 2 significant digits. (d) if the field voltage is reduced by 1/2, calculate the new stall torque (in nm) of the motor (f). if the field voltage is reduced by 1/2, calculate the new no-load speed (in rad/sec)

Which of the following harmful chemicals are found in tobacco smoke? a. carbon monoxide b. carbon dioxide c. nicotine b. carbon dioxide d. both a and c