Answer
See answers.
Work Step by Step
a. Use Ohm’s law to find the current.
$$I=\frac{V}{R}-\frac{120V}{3.0\Omega}=40A$$
b. As discussed on page 599, find the back emf from the normal operating current.
$$\epsilon_{applied}-\epsilon_{back}=IR$$
$$\epsilon_{back}=\epsilon_{applied}-IR=120V-(2.0A)(3.0\Omega)=114V$$
c. Use equation 18–6a to find the power dissipated under normal use.
$$P=I^2R=(2.0A)^2(3.0\Omega)=12W$$
d. Use equation 18–6a to find the power dissipated in the motor coils when the blender is jammed.
$$P=I^2R=(40A)^2(3.0\Omega)=4800W$$