Effects of Frictional Force

Introduction:
Frictional force is a force that opposes the relative motion between two surfaces in contact. It is caused by the irregularities present in the surfaces of objects. Frictional force can have various effects on the motion and behavior of objects.

Explanation:
The correct answer to the question is option 'C' - slowing down of a moving object. Let's understand why this is the case and why the other options are incorrect.

a) Change in the shape of an object:
Frictional force does not directly cause a change in the shape of an object. The shape of an object is determined by its composition and structure, not by the frictional force acting on it.

b) Change in the direction of the motion of an object:
Frictional force can influence the direction of motion of an object but it does not directly cause a change in the direction. For example, when a car takes a turn, the frictional force between the tires and the road helps in changing the direction of the car. However, the change in direction is primarily due to the steering mechanism and the driver's actions, not solely because of friction.

c) Slowing down of a moving object:
Frictional force is responsible for slowing down a moving object. When an object slides or rolls on a surface, the frictional force acts in the opposite direction to the motion. This force opposes the motion and reduces the speed of the object. For example, when a car applies brakes, the frictional force between the brake pads and the wheels slows down the car.

d) Acceleration in a moving body:
Frictional force does not cause acceleration in a moving body. Acceleration is the rate of change of velocity, and it is generally caused by the application of a force. Frictional force acts in the opposite direction to the motion and opposes the motion, therefore it can result in a decrease in velocity or deceleration, but not acceleration.

Conclusion:
In conclusion, the correct effect caused by frictional force is the slowing down of a moving object. Friction acts against the motion, reducing the speed of the object. It is important to understand the different effects of frictional force to analyze and predict the behavior of objects in various situations.