Experiments Showing How Friction Affects Motion

1. Inclined Plane Experiment

   • Goal: To see how friction affects objects moving down a slope.
   • Materials: Set up a ramp that can change angles. Put a block on the ramp.
   • Steps: Slowly raise the angle of the ramp until the block starts to slide down.
   • What to Watch For: Write down the angles where the block starts to move. You can find the static friction using this formula:
     $\tan(\theta) = \mu_s$
   • What We Learned: The average static friction for everyday materials is usually between 0.2 and 0.7.

2. Dynamic Friction with Different Surfaces

   • Goal: To compare how different surfaces affect sliding motion.
   • Materials: Use blocks that are the same size and weight on different surfaces like wood, metal, and carpet.
   • Steps: Pull the blocks with the same force and measure how fast they move.
   • What to Watch For: You can find kinetic friction using this formula from Newton's second law:
     $F_{\text{net}} = ma$
   • What We Learned: Common values show that $\mu_k \approx 0.1$ for ice sliding on ice and $\mu_k \approx 0.35$ for rubber on concrete.

3. Trolley Lab

   • Goal: To see how friction changes the movement of a trolley.
   • Materials: Use a trolley on a track with different surfaces.
   • Steps: Time how long it takes the trolley to travel a fixed distance on each surface.
   • What We Learned: More time means more friction. For example, on a smooth surface, the trolley might go at a speed of $v = 0.5 \, \text{m/s}$, while on a rough surface, it might slow down to $v = 0.3 \, \text{m/s}$.

These experiments help us understand how important friction is when it comes to movement. They also make it easier for students to see how Newton’s laws work in real life.