Question

Opening a door is an example of:
A: contact force
B: non-contact force
C: spring force
D: magnetic force

Answer 1

Hint:We can define force as the external cause or effect that tends to change the state of a body. The change can be either in the direction, shape, size or any such configuration. To find the force that acts on a body, we have to find the nature of the change that occurs in a body.

Complete step by step answer:
Here, we are given a simple condition of opening a door. We use our hands to pull the door towards our direction, or push the door away from our direction. The door can be opened by pushing as well as pulling. When it is done, we are in contact with the body on which the force is applied. Here, it is the door. Thus we can say that a contact force is applied on the door. When we consider the other forces that act on the door, we can find a small amount of frictional force that act on the door hinge. The hinge force is another example of a contact force. Thus, considering the overall forces acting on the body we can conclude that the process of opening a door is facilitated by a contact force.

Thus, we can conclude that option A is the correct answer among the given options.

Note:
Any kind of force can be considered as a push force or a pull force. Pull force is comparatively easier than a push force as it does not involve frictional force for opposition.