InclinedPlaneSimpleMachineSE_Key

Vocabulary:coefficient of friction, efficiency, force, free-body diagram, friction, inclined plane, mechanical advantage, mechanical energy, normal force, resultant force, simple machine, vector, work, work-energy theoremPrior Knowledge Questions (Do these BEFORE using the Gizmo.)[Note: The purpose of these questions is to activate prior knowledge and get students thinking. Students are not expected to know the answers to the Prior Knowledge Questions.]Jan is moving to a new apartment. She needs to load her sofa and other large furniture into a moving van. The rear of the moving van is 1.5 meters high.1.What could Jan use to make loading furniture on the van easier?Answers will vary. Sample answer: Jan could use a ramp to load the furniture.2.Why would this help? Answers will vary. Sample answer: By using a ramp, Jan would not have to directly lift the furniture into the back of the truck.Gizmo Warm-upA simple machinecan be used to make tasks like lifting heavy weights easier. One example of a simple machine is a ramp, or inclined plane. You can use the Inclined Plane –Simple Machine Gizmoto see how inclined planes can help to lift objects.On the CONTROLS pane, make sure the Angleis 30°, the Coeff. of frictionis 0.00, and the Weightis 300 N. 1.The brick has a weight of 300 newtons (N). How much force would it take to lift the brick straight up?Slightly more than 300 N2.Set the External force to On. Set the Applied forceto 100 N and click Play (). What happens? The brick and car slide down the ramp.3.Click Reset ().Using the Gizmo, findthe smallest force that is required to push the block up the 30° ramp.What is the smallest force required? 151N[The nearest slider setting is 155 N.]This study source was downloaded by from CourseH on :57:20 GMT -05:00 2019Activity A: Redirection of forceGet the Gizmo ready:Turn Offthe External force. Click Reset.Set the Angleto 30° and the Weightto 300 N.Question: How does an inclinedplane redirect a force?1.Observe: Select the FREE-BODY DIAGRAM tab. Make sure Magnitudeis on. A free-body diagramis a picture that uses vectorsto show the different forcesacting on an object. What does the purple arrow pointing down represent? The weight of the brickThe inclined plane breaks this force down into two components: one parallel to theinclinedplane (W||) and one perpendicular to the inclined plane (W).2.Infer: Which force (W||or W) will cause the brick to slide down the plane? W||3.Calculate: To calculate a ratio, divide the two numbers being compared.A.What is the ratio of W|| to the Weightof the brick? 0.5B.What is the ratio of Wto the Weightof the brick? 0.8667C.Sine (sin), cosine (cos), and tangent (tan) areratios of the lengths of a right triangle’s sides. Use a calculator to find the sin, cos, and tan of the inclined plane’s Angle. Sin: 0.5Cos:0.866Tan: 0.5774.Synthesize: Describe any relationships you see between the ratios you calculated and the sine, cosine, and/or tangent of the inclined plane’s angle.The ratioof W||to the weight of the brick equals the sine of the plane’s angle, and the ratio of Wto the weight of the brick equals the cosine of the plane’s angle5.Make a rule: Use the relationships you found to write a formula for W||and Win terms of weight (W) and angle (θ):W=W(cosθ)W||= W(sin θ)6.Apply: If the brick’s weight is 500 N and the plane’s angle is 40°, what will W||and Wbe? Use the Gizmo to check your answer.W=383.02 NW||= 321.39 N(Activity Acontinuedon next page)This study source was downloaded by from CourseH on :57:20 GMT -05:00