When the motor below is connected to the battery, the iron bar and copper coil spin in a circle. If no energy is lost as heat and no electrical energy remains after it runs through the coil, how much of the electrical energy flowing through the copper wire is transformed into mechanical energy?
A.
all of it
B.
half of it
C.
none of it
D.
a tiny fraction of it

The temperature in gavin's oven is a sinusoidal function of time. gavin sets his oven so that it has a maximum temperature of 280°f and a minimum temperature of 240°. once the temperature hits 280°, it takes 20 minutes before it is 280° again. gavin's cake needs to be in the oven for 30 minutes at temperatures at or above 270°. he puts the cake into the oven when it is at 260° and rising. how long will gavin need to leave the cake in the oven? (round your answer to the nearest minute.)