Question

Four students push on a block of wood with the forces shown in the diagram below. Assume friction is negligible.





What is the net force acting on the block? Are the forces balanced or unbalanced? How will the block move?

a
The net force on the block is 25 N. The forces are balanced. The block will move to the left.
b
The net force on the block is 25 N. The forces are balanced. The block will move to the right.
c
The net force on the block is 11 N. The forces are unbalanced. The block will move to the right.
d
The net force on the block is 11 N. The forces are unbalanced. The block will move to the left.
e
The net force on the block is 11 N. The forces are balanced. The block will move to the left.
f
The net force on the block is 25 N. The forces are unbalanced. The block will move to the left.
g
The net force on the block is 11 N. The forces are balanced. The block will move to the right.
h
The net force on the block is 25 N. The forces are unbalanced. The block will move to the right.

Answer 1

I can’t see the diagram you mention — could you either attach the image or list the four force magnitudes and their directions? With that I’ll compute the net force and say whether the forces are balanced and which way the block will move.

How to do it (so you can check quickly):
- Choose a positive direction (e.g., right = +).
- Add the forces pointing right and subtract the forces pointing left (or sum rightward forces minus leftward forces).
- If the result is 0 the forces are balanced (no acceleration). If nonzero they are unbalanced and the block accelerates in the direction of the net force.