AIM
In the experiment the effect of different surface textures on frictional force was studied. It was shown that the coefficient of frictions and the maximum static frictional force is determined by the texture (how rough) the surface is. The greater the roughness the greater the maximum static frictional force
HOW DOES IT WORK?
Time Allocation: 45 Min
The track is covered with one of the materials provided in the box. The block, of which the mass has been determined with the scale, is placed on the surface and one end of the track is lifted carefully until the block just starts sliding down. The coefficient of static fraction is calculated with the formula μs = tanθ. The maximum static friction for the specific surface can now be calculated with fsmax = μsN. The normal force is equal to the component of the weight of the box perpendicular to the surface. Learners can verify their answer by
MATERIALS:
- A rectangular block that has a hook attached to one end
- Materials with different textures, e.g. sand paper, wax wrap, card board, smooth varnished, surface
- Electronic scale
- Surface (trolley track) of which the inclination can be changed
METHOD:
- Use the electronic scale to determine the mass the wooden block.
- Cover the surface of the trolley track with one of the materials provided.
- Put the block on the track and lift the one end of the track carefully until the block just starts moving.
- Determine the inclination of the track with the protractor.
- Repeat the experiment – cover the track with different materials and note the angle each time.