Answer question for 10 points
during chemistry lab, mrs. black’s students placed an antacid tablet in a zip lock bag. they recorded the mass of the tablet in the bag. then they carefully added 50 grams of water and quickly sealed the bag. the tablet began to fizz and soon disappeared. the bag was filled with gas and it felt cold to the touch.
what type of change occurred in the bag and how can you support your answer?
a)
it is a physical change because the tablet dissolved.
b)
it is a physical change as evidenced by change in temperature.
c)
it is a chemical change due to the change in temperature and gas production.
d)
it is a chemical change because the tablet dissolved and the temperature of the liquid dropped.

If forces acting on an object are unbalanced, which factors may result fron an unbalanced force? check all that apply

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 are appropriate acceleration units?