2. Escape speed(a) Write the formula of the escape speed starting from the total energy (kinetic energy + gravitational potential energy) and explain how you derived it.(b) The escape speed from the “surface” of the Sun is 620 km/s, and the radius of the Sun is 7.0 × 105 km. Imagine that the Sun kept exactly the same mass, but was compressed to a much smaller radius. Compute the escape speed from the surface of the compressed Sun if the Sun is compressed to roughly the size of the Earth, with a radius of 7000 km. Give your answer in km/s.(c) Compute the escape speed from the surface of the compressed Sun if the Sun is compressed to a radius of 70 km. Give your answer in km/s.Hint: starting from the formula you obtain on point (a), write the ratio between escape velocity for the sun and the compressed sun.