Question

Motion of the wheel of a bicycle is ________________ (projectile, circular) motion.

Answer 1

Hint: The shape of the wheels of a bicycle is circular, so we can directly say that it moves in circular motion. Although, we will first understand both types of motion given to us and their properties and will see, property of which motion matches the most with the motion of wheels of the bicycle.

Complete step by step solution:
We will first understand the two given types of motion, the projectile and the circular motion.

Projectile motion is a form of motion that occurs, when a body moves along a curved path and in no presence of any other force except gravity. In this type of motion, the air resistance is also considered negligible. The path travelled is of a parabola shape but can be a straight line, if thrown vertically upwards. The acceleration due to gravity acts downward and because of the inertia of the object, external horizontal force is not required to maintain horizontal velocity component. Bullets, water from fountains, golf games all these are based on projectile motion.

When an object’s movement is along its circumference of a circle or if it rotates along a circular path with constant speed and angular rotation rate or changing rotation rate, then the object is said to be in circular motion. The rotation happens around a central axis. The velocity vector of any point on the circumference of rotation keeps changing direction and the centripetal force always acts in the direction of the centre of rotation. Examples of such types of motions are ceiling fans, satellites etc.

Since, the wheels of a bicycle also move along a circumference of a circle, its motion is circular in nature.

Note: We can notice while riding a bicycle that the velocity vector of every point of a circle during a circular motion keeps changing. The point of the circumference that touches the surface has its velocity vector direction opposite to that of the direction of the bicycle.