Answer:
The acceleration is 
Explanation:
From the question we are told that
The lift up speed is 
The distance covered for the take off run is 
Generally from kinematic equation we have that

Here u is the initial speed of the aircraft with value 0 m/ s give that the aircraft started from rest
So

=> 
Helium has an atomic mass of 4.00 atomic mass units.
Answer:
D. Asthenosphere
Explanation:
The asthenosphere is relatively plastic part of the mantle which underlies the brittle lithosphere. In the asthenosphere, it is generally believed that the rocks are in ductile state and easily moves. It is the site of convection within the earth. In mantle convection, hot and light materials rises and keeps moving into upper crustal levels till they solidify. Here also, cold and denser materials sinks deeper till they turn to melt. This differences in temperature and density sets up a convective cell within the mantle. Several convective cells are in the mantle.
We have no idea. There are probably many things involved ... the planet's mass,
the availability of small bodies in the neighborhood that can be captured, etc.