A spherical non-rotating planet (with no atmosphere) has mass m1= 5 ×1024 kg and radius r1= 8000 km. A projectile of mass m2≪m1 is fired from the surface of the planet at a point A with a speed vA at an angle α=30∘ with respect to the radial direction. In its subsequent trajectory the projectile reaches a maximum altitude at point B on the sketch. The distance from the center of the planet to the point B is r2=(5/2)r1. Use G=6.674×10−11 kg−1m3s−2.

Question

What is the initial speed vA of the projectile? (in m/s)

Answer 1

http://web.mit.edu/8.01t/www/materials/InClass/IC_Sol_W13D1-8.pdf