The two forces must be equal and opposite.
Two objects must be touching and it has to transfer heat
The two categories of forces are contact forces, which occur when two objects are physically touching, and non-contact forces, which act between objects that are not in direct physical contact.
Balanced forces occur when two forces acting on an object are equal in size and opposite in direction, causing no change in the object's motion. Unbalanced forces occur when the two forces are unequal in size, causing the object to accelerate in the direction of the larger force.
Two types of contact forces are frictional forces, which occur when two surfaces are in contact and resist relative motion, and normal forces, which act perpendicular to the contact surface to prevent objects from passing through each other.
There is no such thing as a balanced force or an unbalanced force. A groupof two or more forces may be balanced or unbalanced. The group of forces isbalanced if the vector sum of all the forces in the group is zero.
In physics, there are two main groups of forces: contact forces and non-contact forces. Contact forces require physical contact between two objects to occur, such as friction, tension, or normal forces. Non-contact forces, on the other hand, act at a distance and do not require direct contact, like gravity, electromagnetism, and nuclear forces.
two molecules must collied before diffusion happens.
For refraction to occur, the light must be passing from one medium to another, the angle of incidence must be different between the two mediums, and the speed of light must change as it travels between the two mediums.
The two forces occur at the same time. Sometimes it is a bit arbitrary which force you call "action", and which "reaction". Just remember that forces always occur in pairs.
Ribosomes make protein.
mating must happen randomly
A merger occurs when two or more businesses join forces to become one organization.