1. helicopter J starts at a elevation of 1400 feet and descends at 8 feet per second at the same time a second helicopter K flying at 1500 ft starts to descend at 10 ft per a second a.) write an equation to model the elevation of each helicopter b.) what are the helicopters elevations after 20 seconds?after 60 seconds c.) when does one helicopter pass the other what is the elevation when that happens

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?