Speed of light and mass increase

[Vals509]

why is it that as the mass of a body increases greater propulsion is needed to move it, according to relativity. i thought that in a vacuum, an object is a lot easier to propel.

 

[Cyosis]

With greater propulsion you mean acceleration? I don't see what this has to do with relativity. Do you mean that E tends to infinity when v approaches c for an object with mass?

A body whether in vacuum or on Earth still has inertia. F=dp/dt still holds even in relativity, although you will need to use relativistic momentum for p. The advantage of vacuum is the lack of resistance, like friction, which makes it easier to accelerate.

 

[Entropia]

According to Einstein's theory of relativity, the speed of light is a constant and is not affected by the mass of an object. However, as an object's mass increases, its energy also increases, making it more difficult to accelerate to high speeds.

This is because the mass of an object is directly related to its energy through the famous equation E=mc². As the mass increases, so does the energy required to accelerate it. This means that a greater amount of propulsion is needed to move a heavier object.

It is important to note that this effect is only significant at speeds close to the speed of light. In everyday situations, the increase in mass is negligible and does not have a noticeable effect on the amount of propulsion needed.

In a vacuum, there is no air resistance, which can make it easier to propel an object. However, the increase in mass still plays a role in the amount of propulsion needed, regardless of the presence of air resistance.

Overall, the relationship between mass and propulsion is a fundamental aspect of relativity and helps us understand the behavior of objects at high speeds.