Hint: The role of a mudguard in a vehicle is to prevent it from throwing off mud and water onto the passerby. Inertia is defined as the property of matter that will continue to stay in the position of rest or motion unless acted upon by an external force. While doing this question consider the three types of inertia.
Complete step by step answer: Among the three types of inertia that is inertia of rest, inertia of direction and inertia of motion, the inertia of direction causes the rotating wheels of the motor vehicles to throw out mud or other type of debris tangentially. Inertia of direction: When the body continues in the state of motion in the same direction unless an external force is acted upon it. According to inertia the matter will continue to stay in motion unless acted upon by a force, therefore the mud will be thrown off onto the passersby. The mudguards placed over the wheels prevent this debris from flying off to the passerby or the driver of the bike or motorbike.
Note: There are three types of inertia; inertia of rest, inertia of direction and inertia of motion. Inertia of rest: body remains in the state of rest unless an external force is acted upon it whereas according to the inertia of motion, the body will continue in the state of motion unless acted upon by a force. Some everyday examples of inertia are the sudden jerk experienced when lift suddenly starts or the tendency to move forward when a sudden break is applied.