Answer:
The value is 
Explanation:
From the question we are told that
The speed of each train is 
The speed of the bird is 
The distance between the trains is 
Generally the time taken before the collision occurs is mathematically represented as

=> 
=>
The total distance covered by the bird is mathematically represented as

=> 
=> 
Answer:
Incomplete third question
I think it should be
C. What was her average speed
Explanation:
Check attachment for solution
A telescope in space can focus on any object while a telescope on the ground cannot focus on the object it is on
Option (B)is correct.
Alternating electric and magnetic fields has electromagnetic radiation that travel in the form of a wave.
The varying or alternating electric field produces the varying magnetic field.This varying magnetic field in turn produces varying electric field . Thus these varying electric and magnetic fields travel in the form of electromagnetic waves. These electromagnetic waves travel with the velocity of light.These are transverse in nature.
Force = 0.20N .F = m ×a .& a = v/t then the f = m×v/t