The scrapyard uses a big electromagnet to move around large metal objects such as cars and appliances. If the operator needed to drop a car to a new space, what would he need to do for this to happen?
A) The magnetic field cannot be turned off.
B) The magnetic field can be turned off by switching off the current.
C) The magnetic field can be reversed by switching the poles of the core.
D) The magnetic field can be decreased by placing it in proximity to an opposite pole.

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.)