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.
First, we have the weight of the brick, which is the force exerted due to gravity. Let's call this force Wbrick.
Secondly, we have the tension force, T, exerted by the cord attached to the brick.
When the brick is resting on the table and in equilibrium, the forces acting on it must balance out. This means that the sum of the forces in the vertical direction (up and down) must be zero.
The normal force is the force exerted by a surface to support the weight of an object resting on it. It acts perpendicularly to the surface.
In this case, the normal force of the desk on the brick counteracts the weight of the brick, so it must be equal in magnitude but opposite in direction to the weight of the brick.
Therefore, the magnitude and direction of the normal force of the desk on the brick is Wbrick in the opposite direction, which is option B) Wbrick - Tcos.