A 12kg box sits on top of a 38kg box.
a) Draw an FBD for each box.
b) Calculate the normal for acting on the 12kg box.
c) Calculate the normal force acting on the 38kg box due to the floor.
a)
FBD for the 12kg box:
- There is a downward gravitational force (mg) acting on the box.
- There is an upward normal force (N) acting on the box due to the 38kg box underneath it.
FBD for the 38kg box:
- There is a downward gravitational force (mg) acting on the box.
- There is an upward normal force (N') acting on the box due to the floor.
- There is a downward normal force (N) acting on the box due to the 12kg box above it.
b) The normal force acting on the 12kg box is equal in magnitude but opposite in direction to the force exerted by the 38kg box below it. Therefore, the normal force acting on the 12kg box is equal to the weight of the 38kg box, which is given by:
N = mg = 38kg * 9.8m/s^2 = 372.4 N
c) The normal force acting on the 38kg box due to the floor is equal to the sum of the weight of the 38kg box and the normal force exerted by the 12kg box above it. Therefore, the normal force acting on the 38kg box is given by:
N' = mg + N = 38kg * 9.8m/s^2 + 372.4 N = 748.4 N