Question

Identify the correct order in which the value of normal reaction increases when an object is placed on rough horizontal surface.
a. The object is pushed with the force $F$ at an angle $\theta$ with horizontal.
b. The object is pulled with the force $F$ at an angle $\theta$ with horizontal.
c. The object is pushed down with the force $F$ normally.
d. The object is pushed up with the force $F$ normally.

• A. a, b, c, d
• B. d, b, a, c
• C. a, c, b, d
• D. b, d, c, a

Answer 1

The correct option is B d, b, a, c

1- When force is perpendicular to surface in the upper direction, that means it decreases the normal force exerted by the surface on the body by newtons 3rd law. D
2-When body is being pulled by some force, one component of force be perpendicular to surface in the upper direction and other is parallel to surface. This perpendicular component decreases the normal force exerted by the surface on the body. B
3- When the body is being pushed by some force, one component of force becomes perpendicular to surface in the downward direction and other is parallel to surface. This perpendicular component increases the normal force exerted by the surface on the body. A
4- When force is perpendicular to surface in the downward direction, that means it increases the normal force exerted by the surface on the body. C