4. The speed of a d. c. motor increases with increasing current through the armature coil. Given fixed supply voltage, two ways of changing the current supplied to the motor are: (1) a variable resistor (potentiometer) or (2) pulse width modulation (PWM). Explain how each method works. Provide one advantage and one disadvantage of each method.

The midpoints? a, b, and c are marked on the histogram. match them to the indicated scores. which? scores, if? any, would be considered? unusual?

(01.02 mc) nicole pushes her bike up a hill. overhead, the sun exerts a gravitational force on earth. which statement is true about the bike and earth? they both experience contact forces. they both experience non-contact forces. the bike experiences a non-contact force and earth experiences a contact force. the bike experiences a contact force and earth experiences a non-contact force. they both experience non-contact forces.

Abucket full of water weights 4 kg and water well is 10m deep. a girl draws water from the well. it takes the girl 3 minutes to draw a bucket full of water from the well. what is the power of the girl?