Electrostatic force between uniformly charged hemispheres consider a uniformly charged sphere with radius r and total charge q. show that the top half exerts a net force on the bottom half given by f =- 641ter2 hint: what is the net force that the top half exerts on the top half?

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.)