When you're talking about gravity, it's easy to identify the equal
opposite forces.
Gravity ALWAYS produces an equal pair of opposite forces.
They both act between the centers of the two objects, one in
each direction.
Consider the equal pair of opposite gravitational forces between
you and the Earth. One force acts on you, and draws you toward
the center of the Earth. We call that force "your weight".
The other one acts on the Earth, and draws it toward the center
of you. Hardly anybody ever talks about that one, but the two
forces are equal ... your weight on Earth is equal to the Earth's
weight on you !
Answer:
150000000000 m
0.0000005 seconds
33.33 ns
Explanation:
Speed of electromagnetic waves through vacuum = 
Echo time = 1000 seconds
Echo time is the time taken to reach the object and come back to the observer
Distance = Speed×Time

Venus is 150000000000 m away from Earth
Time = Distance / Speed

Echo time will be twice the time

The echo time will be 0.0000005 seconds
Difference in time = Difference in distance / Speed

The accuracy by which I will be able to measure the echo time is 33.33 ns
Answer:
I'm sorry but I dont really know this answer
Surveys are considered the most reliable way to gather data