Answer:
hat the speed of the rocket is lower than the minimum escape velocity whereby the ship cannot escape the planet
Explanation:
To find out if the projectile can escape the planet, let's find the minimum escape velocity using the concepts of energy.
Starting point. On the planet's surface
      Emâ â = k + U = ½ m v² - G mM / R²
End point far away
     Emf = U = - g m M / r²
     Emâ = Emf
     ½ m v² - G m M / R² = -G m M / r²
     v² = G M (1 / R² -1 / r²)
Let's find the velocity for the height of the rocket r = 4R
     v =âGM (1 / R² - 1/16 R²) = âa GM / R²    0.968
This is the speed to escape planet
Â
Let's compare this minimum escape velocity with the given value
      Â
      v = âGM /R²   1 /â 3
      v = âGM / R 0.577
We can see that the speed of the rocket is lower than the minimum escape velocity whereby the ship cannot escape the planet