Many science fiction spaceships are powered by antimatter reactors. Suppose a 20-m-long spaceship, with a mass of 15,000 kg when empty, carries 2000 kg of fuel: 1000 kg each of matter and antimatter. The matter and antimatter are slowly combined, and the energy of their total annihilation is used to propel the ship. After consuming all the fuel and reaching top speed, the spaceship flies past a space station that is stationary with respect to the planet from which the ship was launched. What is the length of the spaceship as measured by astronauts on the space station?

NEWTON: THE MIND THAT FOUND THE FUTURE ● different laws had to apply on earth and in the heavens ● science begins from theories or hypotheses that you have to prove ● in newton’s time, the gravity was in the apple ● all forces (including gravity) are between two objects, acting equally on both ○ newton’s 3rd law ● the natural path of a speeding object is a straight line, constant speed ○ uniform motion ● newton’s 1st law ● according to Halley, the force of gravity varies inversely with the square of the distance ● newton’s law of universal gravitation = everything attracts everything else ○ force is directly proportional to the two masses ○ force is inversely proportional to the separation of their ce