March 30, 2019
This is the experimental setup to determine the friction between a block of wood and different types of surface 👉
- Connect a newtonmeter to a block of wood.
- Masses are placed on the block of wood to make sure that block of wood is always in contact with the surface. The masses should be kept constant because it is a controlled variable.
- Start pulling the block wood by newtonmeter and measure the force when the block of wood just starts moving.
- Repeat the experiment on different types of surface, and also repeat the experiment a few times for each surface and calculate the average.
If you conduct the experiment on five different surfaces, you might get results that's similar to this 👇
The friction is very low on ice but high on sandpaper.
Experimental Errors
When you compared your results to your classmates', you found that they have different values. What are some reasons for the difference?
- The surfaces are not uniformly smooth, or the block of wood did not move evenly across the floor.
- Reading the newtonmeter at different angles can cause parallax error.
- The block was not pressed down onto the surface evenly.
- The force was not measured at the instant when the block starts moving; once the block starts moving, less force is needed to keep the block moving.
Decreasing friction
What are some ways that you can decrease the friction?
- Apply some lubricant on the bottom of the block of wood.
- Make sure that the surface has no rough parts and is perfectly smooth.
- Decrease the masses on the block.