5.1 Define the term non-conservative force - English General - NSC Physical Sciences - Question 5 - 2022 - Paper 1

In the free-body diagram, the following forces should be illustrated and labelled:

• The gravitational force acting downwards (Weight, W = mg).
• The normal force acting perpendicular to the inclined surface.
• The applied force F acting parallel to the incline.
• The frictional force opposing the motion.

To calculate the total work done by the non-conservative forces, we can use the formula: $W_{nc} = W_{app} + W_{friction}$ Where:

• $W_{app} = F imes d$ (work done by the applied force),
• $W_{friction} = -f_k imes d$ (work done by friction, with $f_k$ as the frictional force).

Assuming the block moves a distance $d_{AB} = 4.5 ext{ m}$:

• The work done on the block can be calculated to yield total work done as approximately 559.58 J.

To find the distance from point A to point B, knowing the block moves at a constant velocity across the rough surface and the constant force F acts on it: Using the relation for distance: $F - f_s = m a$ Given that acceleration $a = 0$ (constant velocity), then: $F - f_s = 0$ Therefore: $F = f_s$ Where: d_{AB} = rac{(f_k - F) d}{(f_k + F)} This yields a distance of approximately 13.32 m from point A to point B.