Answer:
Explanation:
According to Newton's third law, every action has an equal and opposite reaction
so it tells us that the force exerted by the earth on the spacecraft is equal to the force exerted by the spacecraft on the earth. But we do not see the earth moving towards the spacecraft because the inertia of the spacecraft is very less than the inertia of the earth.
Answer:
Force on the object is 20 N
Explanation:
As we know that work done to raise the book from initial position to final position is known as potential energy stored in it
So here we know that

here we know that
U = 30 J
s = displacement = 1.5 m
so we have


Answer:
The idea behind space expansion is that after the big bang, the universe started infinitely expanding. It's also called metric expansion. Stephen Hawking's A Brief History of Time goes further into detail on this.
Answer:
Through Photosynthesis and Respiration Process.
This depends on whether the pipe is closed or open ended.
The fundamental frequency of a pipe is the simplest, smallest portion of a wave that can fit into a pipe. At the open end of a pipe, there is always an antinode - an area with maximum air movement.
If it is an open ended pipe, there is an antinode at each end, meaning that the length of the pipe is equal to 1/2 <span>λ
</span>. Manipulating the formula <span><span>v=fλ</span>
</span> to solve for the fundamental frequency leaves us with <span><span>f=<span>v/<span>2L</span></span></span>
</span> in an open ended pipe.