Answer:B
Explanation:
Given
Distance of astronaut From asteroid x is 
Distance of astronaut From asteroid Y is 
Suppose M,M_x,M_y be the masses of Astronaut , asteroid X and Y
If the astronaut is in equilibrium then net gravitational force on it is zero


cancel out the common terms we get




A vaccum unlike sound,light can travel through any matter including a great vacuum of nothing (space)
Answer:
True
Explanation:
when the object is larger , the inertia of the object is larger so its tendency to change its state of motion is reduced is reduced.
Explanation :
The forces acting on hot- air balloon are:
Weight, (W)
Force due to air resistance, (F)
Upthrust force, (U)
Its weight W is acting in downward direction. The upthrust force U acts in upward direction. When the balloon is moving upward, the air resistance is in downward and vice versa.
In this case, the hot-air balloon descends vertically at constant speed.
so, 
and 
so,
....................(1)
when it is ascending let the weight that it is releasing is R, so
..........(2)
solving equation (1) and (2)

2F is the weight of material that must be released from the balloon so that it ascends vertically at the same constant speed.