Physics – 1.5.2 Turning effect of forces | e-Consult

Answer: An object remains at rest when there is no resultant force acting upon it and no resultant moment about any point. In this scenario, the vertical force of 20N and the horizontal force of 15N act on the object. The resultant force is the vector sum of all forces. The vertical component of the resultant force is 20N. The horizontal component of the resultant force is 15N. Since these forces are not equal and opposite, the resultant force is not zero. Therefore, the object would accelerate. However, the question states that the object remains at rest. This implies that there must be some other force acting on the object that counteracts the resultant force. The most likely explanation is that there is an upward reaction force from the surface of the object that is equal in magnitude and opposite in direction to the applied forces. This reaction force would balance the resultant force, resulting in a resultant force of zero.

A resultant force is the vector sum of all forces acting on an object. It determines the acceleration of the object. A resultant moment is the vector sum of all moments about a chosen point. It determines the rotation of the object.