GIZMOS STUDENT EXPLORATION: UPDATED ANSWER KEY ON INCLINED PLANES
estion: What determines the helpfulness of an inclined plane?
1. Observe: Use the Gizmo to find the minimum force needed to push the brick up the ramp.
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GIZMOS STUDENT EXPLORATION: UPDATED ANSWER KEY ON INCLINED PLANES
estion: What determines the helpfulness of an inclined plane?
1. Observe: Use the Gizmo to find the minimum force needed to push the brick up the ramp.
A. What is the minimum applied force needed? >48 N
B. Select the FREE BODY DIAGRAM tab. What is the magnitude of W||? 48 N
C. How much force would be required to lift the object directly? >200 N
2. Write a formula: Because less force is needed to lift an object using an inclined plane, it has
a mechanical advantage. The mechanical advantage is equal to the force needed to lift the
object directly divided by the force needed to push the object up the inclined plane.
Write a formula for mechanical advantage (MA) of a ramp in terms of weight (W) and W||:
MA = W ÷ W|| [W is the force required to lift the object directly, and W|| is the force
required to push the object up the inclined plane.]
3. Calculate: Use your formula to calculate the mechanical advantage of the inclined plane on
the SIMULATION pane: 200 N ÷ 48 N = 4.17
4. Write a formula: In activity A, you found the formula for W|| in terms of weight (W) and the
inclined plane’s angle (θ). Substitute this formula into your mechanical advantage formula
and create an equation for mechanical advantage in terms of just the angle (θ):
MA = 1/sin θ [W|| =W(sin θ), so W / W|| = W / W(sin θ) = 1/sin θ]
5. Predict: Based on your formula, how will the mechanical advantage of an inclined plane
change if the angle of the plane is increased or decreased? Explain your answer.
Predictions and explanations will vary. [The mechanical advantage increases as the angle of
the plane is decreased.]
6. Test: Test your ideas using the Gizmo. What did you find?
The mechanical advantage increases as the angle of the plane decreases because W||
decreases as the angle decreases.
(Activity B continued on next page)
Activity B (continued from previous page)
Get the Gizmo ready:
Select the SIMULATION and CONTROLS tabs.
Click Reset. Set the Angle to 14°, Coeff. of
friction (μ) to 0.00, and the Weight to 200 N.
A
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