1. The value of the speed of light, c, is said to be constant at 186,000 miles per second when it is in vacuum. What is its value in kilometers per second, given that 1 mile = 1,609.34 meters? Express your answer in scientific notation and in three significant figures. (10 pts.) 2. Electrons are the negatively charged subatomic particles and are located outside the nucleus of an atom. One single electron has a mass of 9.11 x 10-31 kg. What is an electron's mass in pounds (1b.) if 1 gram = 0.002205 1bs.? Express your answer in scientific notation and in five significant figures. (10 pts.) 3. Sagittarius A, the supermassive blackhole at the center of the Milky Way galaxy, is around 1,500 lightyears away from the Earth. How far is Sagittarius A from Earth in centimeters? Hint: 1 lightyear = 9.461 x 1015 m and 1 m = 100 cm. Express your answer in scientific notation and in five significant figures. (10 pts.)