Which of the following affect friction (you can choose more than 1)a) heightb) weightc) lengthd) roughness of surface

The friction will be mostly affected by roughness of the surface and weight of the object.

Both B & D

Explanation

Friction is the resisting force acting on an object which is on motion on another object or surface. It is a contact force.

Thus the frictional force depends on the two factors,

(i)  the nature of the surface of two objects and

(ii) the mass of the object which needs to moved.

It is known that frictional force is maximum if the surface is roughest.

The smooth surface have less friction so we can move an object easily on a smooth polished surface with less energy than on a rocky surface.

Also from Newton's second law, it is known that any kind of force is directly proportional to the mass of the object and acceleration exerted by the object (F=ma).

As friction is also a kind of force, the influence of mass will be definitely acting on the frictional force.

An object with heavy weight tends to have greater frictional force than on object with less weight.

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide