Atrain leaves the station at 5 am at 60 km/h. another train leaves the same station at 6.30 am at 75 km/h and travels in the direction of the first train. at what time and at what distance from the station will they meet?
a. 12: 30 am - 450 km
b. 1: 30 pm - 375 km
c. 11: 30 am - 425 km
d. none of these

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?