IAW AFI-36-2903, para:6.2.9.1, Cap may not be pushed, rolled, folded or tucked in (e.g. ranger fold).
No
2
The force that makes objects roll is gravity
The gravitational force is.
gravity
A force acting on it.
It can slide if there is enough force to overcome static friction. Similarly, it can roll if the force is great enough to impart a sufficiently large turning moment (and maintain it).
friction
gravity
Gravity
The heavy the crayon, it will roll down but it needs force to move it back up
The Earth's gravity will force a round object to roll down an incline (slope).