Physics, 05.05.2020 04:03 beelcypher
You place a chunk of naturally radioactive (it means not enriched for nuclear purposes) material on the not very exact scale and scale reads approximately 50 kg. You know that the half-life of this material is 20 days. After 40 days of observation the scale reading will be: Group of answer choices
approximately 50 kg
approximately 25 kg
approximately 12.5 kg
Between 12.5 kg and 25 kg, depending on activity
Answers: 3
Physics, 21.06.2019 22:00
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)
Answers: 1
Physics, 22.06.2019 01:00
Calculate the amount of heat produced when 18000 coulombs of charge is transferred in one hour through a potential difference of 50v
Answers: 3
Physics, 22.06.2019 01:30
The passing of heat through a material while the material itself stays in place. a. radiation b. conduction c. convection
Answers: 2
Physics, 22.06.2019 10:10
Apair of 10μf capacitors in a high-power laser are charged to 1.7 kv.a. what charge is stored in each capacitor? b. how much energy is stored in each capacitor?
Answers: 2
You place a chunk of naturally radioactive (it means not enriched for nuclear purposes) material on...
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