# Newton's First Law straight line speed

• bonbon49
In summary, the question is whether there are any objects in the universe that move at the same speed in a straight line forever. The answer is that light or any electromagnetic radiation in vacuum can move at a constant speed forever, but they do not move in a straight line due to the effects of gravity. This relates to Newton's First Law, which states that an object will remain at rest or in motion in a straight line at a constant speed unless acted upon by an external force.
bonbon49

## Homework Statement

For my A-level homework I have to think whether there are any objects in the universe that move at the same speed in a staight line forever.

## Homework Equations

I am stuck to think of anything - do any exist?

## The Attempt at a Solution

Thanks for the help

What about something with no mass?

that would not be possible.. everything in this universe has mass..

however light or any electro magnetic radiation for that matter, in vacuum, moves with the same speed(3x10^8 m/s) forever..

but objects such as meterorites in the universe change velocity because of mass of nearby planets - is this true?

You titled this "Newton's First Law". Perhaps that has something to do with this problem! What is Newton's first law?

By the way, it is not true that "everything in this universe has mass". In fact, you gave an example in the same post in which you said that. It is, however, true that everything is affected by force.

saiaspire said:
that would not be possible.. everything in this universe has mass..

however light or any electro magnetic radiation for that matter, in vacuum, moves with the same speed(3x10^8 m/s) forever..

But that don't move in a strait line...

or you consider classical mechanics and the speed of light is infinite but move in a strait line, or you consider G.Relativity and light travels at c but don't travel in strait path as there's gravity everywhere. ^_^

EDIT: but for the problem i guess that would be related with 1º law...so, is about direct applying it.

## What is Newton's First Law of Motion?

Newton's First Law of Motion, also known as the Law of Inertia, states that an object at rest will stay at rest and an object in motion will stay in motion at a constant velocity in a straight line unless acted upon by an external force.

## How does Newton's First Law relate to straight line speed?

Newton's First Law directly relates to straight line speed as it explains that an object in motion will continue to move at a constant speed in a straight line unless acted upon by a force. This means that if no external forces act upon an object, it will continue to move at the same speed and direction.

## What is the significance of straight line speed in relation to Newton's First Law?

Straight line speed is significant in relation to Newton's First Law because it demonstrates the concept of inertia. An object will continue to move in a straight line at a constant speed unless a force acts upon it, showing that objects have a tendency to resist changes in motion.

## How does mass affect straight line speed according to Newton's First Law?

According to Newton's First Law, mass does not directly affect straight line speed. However, a larger mass may require a greater force to change its speed or direction due to its increased inertia. This means that an object with a larger mass may appear to have a slower straight line speed than an object with a smaller mass when acted upon by the same force.

## Can an object in motion ever have a constant speed if it is constantly being acted upon by external forces?

No, according to Newton's First Law, an object will only have a constant speed in a straight line if no external forces are acting upon it. If an object is constantly being acted upon by external forces, its speed and direction will change accordingly. This is known as unbalanced forces, where the net force acting on an object is not equal to zero.

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