Lesson 11The Inclined Plane

Getting StartedRemember Lesson 6, friction?

1. What did you find out about friction in lesson 6?

2. When you pulled the blocks in lesson 6, you exerted a force called the effort force to move the blocks at a constant speed. Where was the friction force? Which way did it act?

3. Does friction increase or decrease the amount of work needed to do a task?

Getting Started ContinuedThink of places where you have seen ramps.

1. Have you ever seen a ramp used to move an object or a person onto a platform or to a higher position? If so, where?

2. Did the ramp have a gentle slope or a steep slope?

3. Why do you think a ramp was used?

* A ramp is a type of inclined plane *

Inquiry 11.1 Measuring Forces on a Cart on an Inclined PlaneQuestion: What will happen to the effort

required to move a cart up an inclined plane if the slope is steadily increased?

Hypothesis: I believe . . . Because . . .

Procedure: p.102-103

DataHole # Rise

(cm)Run (cm)

Slope Angle (degrees)

Force (N)

0

3

5

7

9

11

13

15

17

19

21

23

Data ContinuedMake a graph showing the relationship of

slope to effort force.

VocabularyEffort distanceLoad forceLoad distanceGravity

ConclusionLook back at your original question.

Write in complete sentences.

Use and underline all vocabulary terms.

Inquiry 11.2Measuring Work on a Cart on an Inclined PlaneQuestion: How does the work needed to pull

the cart up the inclined plane set at different slopes compare with the work needed to lift the cart straight up?

Hypothesis: I believe . . . Because . . .

Procedure: p. 104-105

Data: Work and the Inclined PlaneHole #

Rise (cm)

Run (cm)

Slope Effort Force (N)

Effort Distance (m)

Work(N-m)

Load Force___________ x Load Distance ____________ = ___________ (work)

Data Questions1. On the basis of the results of these inquiries,

how would you define a machine?2. In you view, is an inclined plane a machine?3. Why are ramps for people with physical

disabilities long and gently sloping, rather than short and steep?

4. Suppose you repeated inquiry 11.2 with a sled instead of a cart. Would you get different results? If so, how would they be different?

VocabularyLoad distanceLoad forceEffort distancework

ConclusionLook back at your original question.

Write in complete sentences.

Use and underline all vocabulary terms.