Through push and pull and the other force is friction
A rough estimate would be about 90-100 people standing on a double-decker bus, depending on the size of the bus and local regulations.
The Normans built around 500 castles of varies types and size throughout England and Wales after the invasion of England in 1066. About 90 are still standing, many intact and still occupied and many in a state of ruin. The link below has more good information about Norman Castles.
Force on accelarating object.
You can estimate the size of forces acting on a car by considering factors such as its mass, acceleration, and friction. Units for force are typically measured in newtons (N) in the metric system and pounds (lbs) in the imperial system. By calculating the force required to accelerate the car or overcome friction, you can estimate the magnitude of forces involved.
It is highly unlikely for a woman of average size to crush a man to death simply by standing on him. The amount of force required to cause such significant harm would not typically be exerted through this kind of interaction.
The size of the normal force and coefficient of friction determines the size of frictional force.
As of 2013 May 15, Grand Canyon still stands. Considering its size, it will take quite a bit of effort to keep the Grand Canyon from standing.
The size of a frictional force is determined by the roughness of the surfaces in contact and the normal force pushing them together. The frictional force opposes the motion of the objects and increases with the weight of the objects in contact.
The size is 12 inches standing on two feet and 6 inches standing on all four feet.
A force causes an object to change its motion by accelerating or decelerating it. The direction and magnitude of the force determine how the object will move. If the force is unbalanced, the object will accelerate in the direction of the force.
Force is a vector quantity that has both magnitude (size) and direction. The size of a force is measured in units such as newtons or pounds, and it describes the amount of push or pull being applied to an object.
The "size" of a vector quantity - such as a force - is often called a MAGNITUDE.