Answer:
light doesn't need a medium through which to travel because the speed of light is experimentally constant
Answer:
Explanation:
Gravitational Potential Energy at earth surface 
Gravitational Potential Energy at height h is 
Energy required to lift the satellite 

Now Energy required to orbit around the earth



(given)




(b)For greater height
is greater than 
thus energy to lift the satellite is more than orbiting around earth
Part a)
Magnitude of electric field is given by force per unit charge



Part b)
Electrostatic force on the proton is given as
F = qE


PART C)
Gravitational force is given by



PART d)
Ratio of electric force to weight


Answer:

Explanation:
Potential energy is minus the integral of Fdx. Doing the integration yields:



so


Now for x=3.0m


Answer:
Because in order for work to be done on an object, the object must be moving. Why isn't work being done on a barbell when a weight lifter is holding the barbell over his head? Work is maximized when force is applied in the same direction that the object is moving. ... In order to do work faster, more_is required.