Question

State whether the given statement is true or false:
The earth moves around the sun with a uniform velocity.
(A) True
(B) False

Answer 1

Hint:
We know that our planet earth is in continuous motion on its own axis as well as around the sun in an orbit. According to Kepler’s law, the orbit of the earth around the sun is elliptical in shape. The given statement says that the velocity of the earth is constant while revolving around the sun. Using the concept of velocity we have to find whether it is true or false.

Completer step by step solution:
According to Kepler’s law, we know that all the planets revolve around the sun in elliptical orbits. The velocity of a body is a vector quantity. Vector quantities represent the magnitude as well as the direction of that physical quantity. When we say that a body has uniform velocity it must be moving with the same magnitude of velocity as well as the object must be moving in the same direction at all instants. If we take an object moving in circular or elliptical orbits, even if the magnitude of the velocity is the same at all instants the direction changes at each instant. Hence we cannot say that the earth is in uniform motion around the sun.
Therefore, the given statement is false.

The answer is Option (B): False

Note:
An alternate solution can be that the sun is located as one of the foci of the elliptical orbit of the earth. During perihelion, the earth's orbit is the nearest to the sun and hence it will move with a greater velocity, and during aphelion, that is when the orbit of the earth is farthest from the sun, the velocity of the earth will be lesser than that of perihelion. Hence we can say that earth is not moving with uniform velocity.