Friction

# Friction

 Language: English The concept of friction is something that is always present in every aspect of life. This lesson is designed to help students understand what role mass has on friction and how it ultimately affects acceleration. Key Stage 4, Key Stage 5 Laboratory Friction Knowing what affect mass has on the acceleration of a block down a ramp Being able to derive the appropriate formula to describe the acceleration of a block down a ramp Discuss what forces are present when a block slides down a ramp and list them on the board. Then discuss how increasing or decreasing the mass of the object will affect those forces. Discuss how changing these forces will affect the acceleration of the block down a ramp and challenge them to explain their reasoning with the appropriate physics related terms. Based on what students think will happen, ask them how changing the coefficient of friction will further change the acceleration After students have come to their own hypothesis, have them write it down on a sheet of paper for later. Then discuss how they could test these predictions. Once students have come up with predictions, encourage them to use the Create – Predict –Interact – Evaluate.
Steps in Algodoo

# CREATE A SCENE

Open ‘Friction Lab’ scene above.

# MAKE A PREDICTION

Have students record their predictions about how they think the acceleration of the sled will be affected when they add or subtract mass from it.

# RUN/INTERACT

Using the sled and weights available, test your predictions by filling the sled with different amounts of mass and time how long it takes for the sled to slide down the 10 meter section shown. Using the time, calculate the acceleration of the sled. Repeat this process with different amounts of mass in the sled.

# EVALUATE

As you increased the mass in the sled, how does the time it takes to reach the bottom of the 10 meters change? How does the acceleration down the ramp change? Based on your data, how does changing the mass of the sled affect the acceleration? Derive a mathematical expression that explains the results you found.

# REVISE SCENE

Now try changing the coefficient of friction of the plane to 0.150 by right clicking on it-materials-friction.

# MAKE A PREDICTION

Make a new prediction as to how changing this value will affect the acceleration of the sled down the ramp.

# RUN/INTERACT

Repeat the above process to see how the coefficient of friction affects acceleration.