To increase friction you could : a. increase the mass of an object b. put your objects on a wheel c. make the surfaces smooth or slick

Before going to answer  this question first we have to know something about friction.

Friction is the opposing force which is due to interlocking of irregularity and wielding effect.In our naked eye a surface may  look smooth, but at microscopic level, it has elevations and depressions.

A rough surface has more friction as compared to a smoother surface as smoother surface has less irregularity.

Again we know that that rolling friction is less than sliding friction.so whenever the object will be placed  on a wheel,so there will be less friction.

Again we know that the frictional force is directly proportional to the normal reaction.

The empirical formula for frictional force F= coefficient of friction × normal reaction

so whenever the mass increases ,correspondingly there will be increment in normal reaction which results in the increment in kinetic friction.

But one thing we have to remember that friction is also dependent on contact area.As long as the contact area is same ,there will be no increment in friction due to increment in mass.

So the first answer is partially correct.

c

explanation:

massxgravity x heght=weightxheight= pe

4900=490xh

h=10