The correct option is (c).
Explanation
The motion of the moon around the earth is an approximation of uniform circular motion. In this system, the object moves along a circular path with constant speed, governed by the principles of centripetal force and Newton's Laws of Motion.
Statement-wise Analysis:
- Statement 1 is Incorrect. Although the moon moves at a nearly constant speed, its direction of motion changes continuously at every point on its orbit. Since velocity is a vector quantity comprising both speed and direction, a change in direction implies a change in velocity. Consequently, this motion is accelerated (centripetal acceleration), not a motion with zero acceleration.
- Statement 2 is Correct. To maintain a circular path, a force must act on the body directed towards the centre of the circle. This is called centripetal force. In the case of the moon, the gravitational force of attraction exerted by the earth provides this necessary centripetal force, directed towards the earth's centre.
- Statement 3 is Correct. According to Newton's First Law of Motion (Law of Inertia), an object continues in its state of motion unless acted upon by an external force. The moon possesses a velocity vector tangent to its orbit at every instant. If the gravitational force (the external force) were to cease, the moon would follow the path of its instantaneous velocity, moving in a straight line tangent to the circular path.
Key Takeaway:
Uniform circular motion is always an accelerated motion due to the continuous change in direction. The governing force is centripetal, directed towards the centre, and its absence results in tangential motion due to inertia.