Asilo is constructed using a cylinder with a hemisphere on top. the circumference of the hemisphere and the circumference of the cylinder are equal. the diameter of the circular base of the cylinder is 10 feet. the cylinder is 40 feet tall. one of the circular bases on the cylinder is in contact with the ground.
what is the area of the surface of the silo that will be exposed to rain, wind, and sun?
a. 450π square feet
b. 475π square feet
c. 500π square feet
d. 525π square feet

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?