Friction is a force that opposes motion between two surfaces that are in contact with each other. It is caused by the roughness or irregularities of the surfaces and can slow down or stop the movement of objects.
The angle of the stair rail in this scenario is 40 degrees.
The angle of the stair rail affects the friction by increasing the normal force, which is the force perpendicular to the surface of the rail. This increased normal force results in a stronger frictional force, making it harder for the child to slide down the rail.
There are several factors that can affect the amount of friction in this scenario, including the weight of the child, the material of the stair rail, the surface of the rail (smooth or rough), and the angle of the rail.
To reduce friction in this scenario, you can try using a smoother material for the stair rail, such as metal or plastic, instead of a rough material like wood. Additionally, you can decrease the angle of the stair rail, which will result in a smaller normal force and therefore a weaker frictional force.