Key Questions:
description
Transcript of Key Questions:
![Page 1: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/1.jpg)
![Page 2: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/2.jpg)
Key Questions: What is torque? How do we calculate torque?
![Page 3: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/3.jpg)
Performance Objectives
Measure forces and distances in a simple machine.
Calculate torque.Apply the concept of mechanical advantage to levers.
Build three classes of levers.
![Page 4: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/4.jpg)
Lever Assembly
SAFETY NOTE:WATCH for FALLING weights on bare toes or sandals or table tops!
DO not place the fulcrum higher than hole 3 of stand!
![Page 5: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/5.jpg)
Torque
Levers use torque to lift or move objects.Torque is a force applied over a distance that causes ROTATION to occur.
Torque is measured in Newtonmeters (Nm)
![Page 6: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/6.jpg)
Review of levers
Force x Distance = Force x Distance
Input Force
x Length of Input Arm
Torque
Output Force
x Length of Output Arm
=
Force= DistanceX
![Page 7: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/7.jpg)
An Example of Torque
Calculate the torque created when opening the door.
![Page 8: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/8.jpg)
1. Set up the balanced lever
![Page 9: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/9.jpg)
2. Measure Forces and 3. Calculate input/output torques
![Page 10: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/10.jpg)
Calibrate the spring scale
![Page 11: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/11.jpg)
Data
![Page 12: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/12.jpg)
Torque and direction If more than one torque acts on an object, the
torques are combined to determine the net torque. If the torques tend to make an object spin in the
same direction (clockwise or counterclockwise), they are added together.
If the torques tend to make the object spin in opposite directions, the torques are subtracted.
Torques causing counterclockwise rotation are positive and torques causing clockwise rotation are negative.
![Page 13: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/13.jpg)
Forces and MachinesThe variables in a simple machine can be adjusted make work easier or resist forces on purpose.
Consider two levers:
![Page 14: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/14.jpg)
Forces and MachinesThe advantage the simple machine gives to the user can be calculated.
A machine approaches a mechanical advantage of 1, when output forces roughly equal input forces.
![Page 15: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/15.jpg)
Mechanical Advantage
MA = Fo
Fi
Output force (N)
Input force (N)
mechanicaladvantage
![Page 16: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/16.jpg)
Mechanical advantage
What is the mechanical advantage of this new lever?
![Page 17: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/17.jpg)
Torque and mechanical advantageWhat’s the mathematical relationship between torque and mechanical advantage?
MA = Output Torque ÷ Input Torque
![Page 18: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/18.jpg)
Build different levers…
![Page 19: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/19.jpg)
Three Classes of Levers First Class - fulcrum
between Input and output
Second Class – output between fulcrum and input
Third Class – input between fulcrum and output
![Page 20: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/20.jpg)
Levers and the human body
Your body contains muscles attached to bones in ways that act as levers.
Here the biceps muscle attached in front of the elbow opposes the muscles in the forearm. Can you think of other
muscle levers in your body?
![Page 21: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/21.jpg)
Mobiles are levers!
GREAT STEM project!
![Page 22: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/22.jpg)
Outcomes Use science Think scientifically Communicate technical ideas Teach all students Be science conscious NOT
science phobic
![Page 23: Key Questions:](https://reader036.fdocuments.us/reader036/viewer/2022062810/56815b65550346895dc95686/html5/thumbnails/23.jpg)
What questions do you have about Torque or Mechanical Advantage?