Mechanical Advantage Lesson

Calculating Mechanical Advantage- Ideal or Otherwise.

Physical Science: Jan 2024

Intro

Hello. Remember when in class we looked at the "Machines Slides" linked in our google classroom, and we got to a portion where I said "I don't want to dive too deep into that right now, but we will be coming back to it". This is that time.
Some of you have finished your Rube Goldberg Double Quiz/project and are ready to move ahead. Some of you have not and thats okay.

This is part of the instruction for class (1/22/24). You will either complete it First thing at the start of class Monday or as part of your Homework.
All of you will be given a set of HW questions that are to help you practice the skills you have learned for a Quiz that'll be upcoming.

Intro- Continued

I will link several videos from youtube that I think are helpful to help complete the imbedded problems. I will also provide a slide describing the topics as best I can for each.

Good Luck!!

​Mechanical Advantage

When calculating mechanical advantage it is important to be able to identify the Effort (input) and the Resistance (output) Forces.
Since these are forces you measure them in Newtons.
*Meaning you can calculate some forces if you know the Mass and the Acceleration due to gravity* (F=m*a) (a= 10 m/s/s on earth)

To find Mechanical Advantage you divide the Resistance force by the Effort force. This is a measurement of how many times a machine multiplies the input force. MA= Fr / Fe

I know he used feet in the video. That is okay in this situation because we are looking at the relationship between the length of the sides (a ratio). If you'll notice(@ 3 and a half minutes in) he had his work calculated in Newton feet and not Newton Meters. Hmm.. where have we heard of Newton Meters before? 

​-Mr Devillier

Reorder

Order the Following Machines from Lowest Mechanical Advantage to Highest Mechanical Advantage. Lowest MA @ 1 & Highest MA @ 3

• Effort Force= 25N

  Resistance Force= 175N

• Effort Force= 8N

  Resistance Force= 64N

• Effort Force= 82N

  Resistance Force= 738N

1

2

3

• 1
• 2
• 3

Multiple Choice

Which of the Following Machines has a Mechanical Advantage of 25?

• Effort Force= 804N

  Resistance Force= 20100N

• Effort Force= 168N

  Resistance Force= 4032N

• Effort Force= 461N

  Resistance Force= 10603N

• Effort Force= 621N

  Resistance Force= 16146N

Multiple Choice

Which of the Following Machines has a Mechanical Advantage of 9?

• Effort Force= 185N

  Resistance Force= 1480N

• Effort Force= 17N

  Resistance Force= 153N

• Effort Force= 23N

  Resistance Force= 230N

• Effort Force= 76N

  Resistance Force= 836N

Multiple Choice

How long must the length of the effort arm be to lift a 500kg boulder by applying only 200N of force?

• 20 Times as long as the Resistance Arm

• Effort arm = 80m

  Resistance arm = 2m

• 10 Times as long as the Resistance arm

• Effort arm = 100m

  Resistance arm = 4m

Multiple Choice

Mr Devillier is trying to test out his snazzy new lever. This lever Boasts a Mechanical Advantage of 4.5!!!! How much force could Mr Devillier predict to be able to generate by standing on the other side of the lever? He is 80 kg.

• 2000N

• 850N

• 3200N

• 4000N

Multiple Choice

How much force must be put into a lever to lift a 875 lbs weight? The length of the effort arm is 3.75 ft and a resistance arm of 1 ft.

(1 kg = 2.2 lbs) (1 m = 3.281 ft)

• 3977 N

• 1060 N

• 3975 N

• 1050 N