# Student Portal:

# Friction

#### Friction: Investigation 1 - Frictional Force

In Investigation One, you will use a spring scale to measure frictional force. During this Investigation, you will:

- Push a penny toward a goal line, observed its movement, and measured the distance it traveled.
- Consider positive and negative acceleration as the penny moves.
- Observe the magnitude of force as a woodblock is pulled across the bench with a spring scale.
- Measure the frictional force between the woodblock and the table using a spring scale.
- Calculate the average velocity of the woodblock using the following formula:

- Calculate the sum of all forces using the following formula:

#### Friction: Investigation 2 - Velocity and Frictional Force

In Investigation Two, you will test the influence of velocity on a frictional force. During this Investigation, you will:

- Measure the force required to pull a woodblock 50 cm in the following time segments:
- 2 s
- 4 s
- 6 s
- 8 s

- Calculate the average velocity for each trial using the following formula:

#### Friction: Investigation 3 - Weight, Surface Area, and Frictional Force

In Investigation Three, you will investigate weight and surface area and how they affect frictional force. During this Investigation, you will:

- Determine the mass of each of the following loads:

- Wood box
- Wood box and 100 g
- Wood box and 200 g
- Wood box and 300 g

- Convert mass in grams to kilograms using the following formula:

- Calculate the weight of each load using the following formula:

** Weight (N) = mass (kg) × acceleration due to gravity (9.8 m/s**^{2})

^{2})

- Measure force by pulling a woodblock on each of its (3) surfaces:

- Bottom
- Side
- End

- Calculate the surface area of each of the surfaces on the woodblock by using the following formula:

**Surface area (cm ^{2}) = length (cm) × width (cm)**

#### Friction: Investigation 4 - Surface Type and Frictional Force

In Investigation Four, you will explore the frictional force of different types of surfaces. During this Investigation, you will:

- Pull a woodblock 50 cm to measure the frictional force for surface combinations.

- Measure the mass of the woodblock in grams using a triple beam balance.
- Convert grams to kilograms using the following formula:

- Calculate the coefficient of friction using the following formulas:

**Weight (N) = mass (kg) × acceleration due to gravity (9.8 m/s ^{2})**