The escaping speed formula is $v_{\text{e}\text{s}\text{c}}=\sqrt[\phantom{2}]{\frac{2GM}{R}},M$ is the mass of the planet or the sun for a spaceship to scape from, $R$ is the distance to the center of Earth or Sun from the initial position of the spaceship. a$)$ Prove this formula based on the class note and using algebra. b$)$ And find the escaping speed of the Earth. $2$pt