what is the speed of an object at rest?

Answer 1

speed is distance travelled per unit time.
when an object is at rest, it does not travel any distance i.e. distance = 0.
hence speed = 0, for an object at rest.

Answer 2

That depends on the speed it was traveling at during the time the measurement was taken. For most formulas, it is assumed that the frame of reference is such that the speed of the object appears to be zero.

For example, a book on your desk does not look like it's moving from where you're sitting...at least, we hope not. However, if you were out in space and had a telescope that could see that book, it would appear to be moving at the same speed as the rest of the earth.

I don't think anything in the universe is in a true state of "at rest", so you'd probably have to go with the common assumption that the speed is zero for the sake of the problem.

Answer 3

An Object (Whether Rest Or Moving) Has Many Different Speeds . For Example : You Are In Car , And you Have A Ball In your Hand, The Car's speed Is 30 km/s . Now The Ball's Speed In relative to you is 0 km/s. but in relative to the earth or road is 30 km/s.
even when you are standing in your feet , you have speed , in relative to sun , moon , other planet ,.....

Answer 4

One of the consequences of Einstein's special theory of relativity (1905) is that the mass of an object increases with its velocity relative to the observer. When an object is at rest (relative to the observer), it has the usual (inertial = tendency to resist an applied force) mass that we are all familiar with. This is called the 'rest mass' of the object.

As the speed of the object is increased, the inertial mass of the object also increases. For speeds significantly less than the speed of light, the increase in mass is nearly imperceptible, but as the speed of light is approached, the mass starts to increase very rapidly toward infinity. Theoretically, the mass would become infinite if the object could be accelerated all the way to the speed of light. However, because the acceleration of an object in response to a given force is inversely proportional to its inertial mass, as the speed of light is approached the force required actually to reach the speed of light also becomes infinite. Therefore, it is impossible actually to accelerate an object with non-zero rest mass to the speed of light.

Another way of expressing the fact that a massive object cannot be accelerated to the speed of light is through the concept of energy. That is, an infinite amount of energy would have to be expended, via the accelerating force, to reach the speed of light.
Mass measures the amount of inertia an object has, with inertia defined as the resistance the object offers to a change in its state of motion. While we usually think of mass as being constant for an object, Relativity tells us that energy and mass are interchangeable. Any object in motion has, by definition, Kinetic Energy. That energy has the effect of increasing the object's mass, so the MINIMUM mass of an object is its mass when stationary, or its REST MASS.

Answer 5

Speed is always a relative term..An moving object compared with a relative object and measured..remem' ensteins theory , relativity & so on..

so the speed of the ball relative to you would be zero if you too are standing still next to a still ball.

like somebody has answered the absolute speed is unknown . as it involves the linear velocity of the solar system & also the linear velocity of the galaxy we are in..mmh but compared with what?

but as you could imagine there will not be a frame to sit and watch this the entire galaxy moving..untill you get a relative frame you can never measure the absolute velocity of an object..

You can predictively suggest by wave shifting patterns & other theories...

Answer 6

A body is said to be at rest in a frame of reference when the relative speed between the object and the reference frame is zero.

Answer 7

The object just placed on earths surface is zero, if its placed on a moving object its speed will be the speed of that the moving object.

Answer 8

There is no such thing as a object at rest in fact. Every know object in the universe is in motion. But for the sake of the queston. Relative to the point of reference absolute 0.

Answer 9

as eagleflyer pointed out, all speed is relative. so if you're measuring the object's speed relative to the earth, and the object is "at rest" on the surface of the earth, then clearly the object's speed is zero. if you're measuring its speed relative to some object outside our atmosphere, then the speed will vary considerably based on what object you choose and, if you want to get really nitpicky about it, based on the latitude (again, assuming the object is at rest on the earth's surface) at which the object is located.

Answer 10

As we know this world everything is relative. Hence a reference inertial frame is essential. The speed of an object depends on the reference inertial frame.

When you mention that the object is at rest you have already defined your frame of reference and hence the speed is ZERO.

Answer 11

it depends on what u compare it to. An object at rest on the surface of the earth when being compared to the velocity of the Earth (which is also the velocity of the object on the surface of the earth) would obviously be zero.
Since all velocities are taken on the basis of being compared with the earth's velocity itself, therefore in laymans terms, as stated before, the velocity (or speed) would be ZERO, as pointed out by everybody else who has replied to this question