At time t=0 a grinding wheel has an angular velocity of 26.0 rad/s. it has a constant angular acceleration of 25.0 rad/s^2 until a circuit breaker trips at time t = 2.50 s. from then on, the wheel turns through an angle of 440 rad as it coasts to a stop at constant angular deceleration.
through what total angle did the wheel turn between t=0 and the time it stopped? at what time does the wheel stop? what was the wheel's angular acceleration as it slowed down?

The equations of motions will be applied in this question; except that in this case it will be angular motion instead of linear motion.
We use the formula
v = u + at; to determine the final velocity of before the circuit breaker trips.
v = 26 + 2.5 x 25
= 88.5 rad/s
Total angle covered before circuit breaker trips:
2as = v² - u²
s = (88.5² - 26²)/2(25)
s = 143.125 rad
Angle covered before stopping after trip = 440 rad
Total angle covered from start to finish:
143.125 + 440
= 583.125 rad

Acceleration as wheel stops:
2as = v² - u²; v = 0
a = -(88.5²)/2(440)
a = 0.1 rad/s²

Time to stop:
v = u + at
0 = 88.5 - 0.1t
t = 885 seconds
Total time: 2.5 + 885 
= 887.5 seconds

You will hear a hissing sound because of the carbon dioxide escaping the can or bottle

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.