A heavy wooden block is dragged by a force along a rough steel plate, as shown below for two cases. The magnitude of the applied force is the same for both cases. The normal force in (ii), as compared with the normal force in (i) is:
A) the same
B) greater
C) less
D) less for some angles of the incline and greater for others
E) less or greater, depending on the magnitude of the applied force

Question

A heavy wooden block is dragged by a force along a rough steel plate, as shown below for two cases. The magnitude of the applied force is the same for both cases. The normal force in (ii), as compared with the normal force in (i) is: 
A) the same 
B) greater 
C) less 
D) less for some angles of the incline and greater for others 
E) less or greater, depending on the magnitude of the applied force

Quizplus · Accepted Answer

In case (ii), the block is being dragged up an inclined plane, meaning the normal force must be less than that in case (i), where the block is being dragged horizontally. This is because the weight of the block is now partially supported by the up-component of the normal force, rather than being entirely supported by the force of gravity as in case (i). Therefore, the normal force in case (ii) is less than that in case (i).

A Heavy Wooden Block Is Dragged by a Force Along