A brick rests on a table. A cord is attached to the brick and a tension force, T, is exerted in the brick by the cord.
The magnitude and direction of the normal force of the desk on the brick is equal to
A) Wbrick + Tcos
B) Wbrick - Tcos
C) Wbrick + Tsin
D) Wbrick - Tsin
To determine the magnitude and direction of the normal force of the desk on the brick, we need to consider the forces acting on the brick in the vertical direction.
The normal force is the force exerted by a surface to support the weight of an object resting on it. It always acts perpendicular to the surface. In this case, the desk exerts a normal force on the brick.
The two forces acting on the brick in the vertical direction are its weight (Wbrick) and the tension force (T) exerted by the cord.
To find the magnitude of the normal force, we need to balance the vertical forces acting on the brick. This means that the magnitude of the normal force should be equal to the sum of the magnitudes of the weight and tension force acting in the opposite direction.
Since the weight acts downward and the tension force acts upward, the magnitude of the normal force will be:
Magnitude of the normal force = Wbrick + T
Now, let's consider the direction of the normal force. The normal force always acts perpendicular to the surface. In this case, since the weight and tension force are acting vertically, the direction of the normal force will be in the opposite direction.
Therefore, the correct answer is:
A) Wbrick + T
This choice represents the magnitude of the normal force (Wbrick + T) and the fact that it acts in the opposite direction.