Arocket is launched from the surface of the earth with mass me and radius r, to escape from the earth (a) [10] find the required velocity impulse (or escaping velocity), neglecting the other forces such as air friction. here the velocity impulse is the velocity gain of the rocket under the assumption that the acceleration of the rocket by ejection is done instantly. (b) [10] given that the mass of the rocket without fuel is mo and the ejection velocity is u, find the required initial mass m of the rocket.