Lesson 5

Introduction to Forces

Getting Started•Write what you think you know about forces.

List some forces that are familiar to you.

•Examine your spring scale and answer the following questions:

1. What happens to the reading on the spring scale when you pull horizontally on the scale?

2. What are the units of measure for force on your scale?

3. What is the maximum force that your scale can measure?

4. How much force do the smaller marks along the scale represent?

Question

•What is a force?

Hypothesis

•I believe . . . Because . . .

Procedure

•P. 38-41

Data: 5.1

Stretching Distance (cm)

Elastic Force(N)

0

2

4

6

8

10

12

14

16

18

20

Elastic Force

Data Questions1. What happens to the force required to stretch

the rubber band when the stretching distance is doubled? Review at least 3 instances of doubling the distance.

2. Construct a graph of your data. Review your graphing rules to help you.

3. What does your graph tell you about the relationship between the force needed to stretch the rubber band and the distance it stretches.

4. Did the force needed to stretch the rubber band increase by the same amount each time you stretched the rubber band another 2 cm? Is the answer visible in the graph?

5. Can you predict the force needed to stretch the rubber band to 4o cm? Why or why not?

Data 5.2 Weight vs. Mass

Mass Units(# of Washers)

Weight (N)

1

2

3

4

5

6

Data Questions

1. Construct a graph of your data.

Vocabulary

•Force•Newton•Elastic forces•Gravitational force•Weight•Mass•Gravity

Conclusion

•Write in complete sentences.•Underline all vocabulary terms.