A toy cannon uses a spring to project a 5.31-g soft rubber ball. The spring is originally compressed by 4.90 cm and has a force constant of 8.09 N/m. When the cannon is fired, the ball moves 14.1 cm through the horizontal barrel of the cannon, and the barrel exerts a constant friction force of 0.031 7 N on the ball. Required:
a. With what speed does the projectile leave the barrel of the cannon?
b. At what point does the ball have maximum speed?
c. What is this maximum speed?

On a mild saturday morning while people are working inside, the furnace keeps the temperature inside the building at 23degreesc. at noon the furnace is turned off, and the people go home. the temperature outside is a constant 16degreesc for the rest of the afternoon. if the time constant for the building is 3 hr, when will the temperature inside the building reach 18degreesc? if some windows are left open and the time constant drops to 2 hr, when will the temperature inside reach 18degreesc?