Part 1 A dc motor is connected to a constant emf of 15.6 V. The resistance of its windings is 2.0 ohms. At normal operating speed, the motor delivers 6.8 W of mechanical power.
(a) What is the initial current drawn by the motor when it is first started up?
A
(b) What current does it draw at normal operating speed?
A
(c) What is the back emf induced in the windings at normal speed?
V
Part 2 A transformer with 1817 turns on the primary and 386 turns on the secondary is used in an electric slot car racing set to reduce the input voltage amplitude of 170 V from the wall output. The current in the secondary coil is of amplitude 3.2 A.
What is the voltage amplitude across the secondary coil?
V
What is the current amplitude in the primary coil?
A