Section 14.3 Mechanical Advantage And Efficiency Answer Key Pdf â¢ No Survey

1. Brunelleschiâs Treadwheel Crane
a) ( IMA = \fracd_\textind_\textout = \frac15 , \textm1.5 , \textm = \mathbf10 )
b) ( \textEfficiency = \fracAMAIMA \times 100% = \frac810 \times 100% = \mathbf80% )

2. Hoist Gear System
( AMA = \fracF_\textoutF_\textin = \frac400 , \textN20 , \textN = \mathbf20 )

3. Pulley Efficiency
( \textEfficiency = \frac4.56 \times 100% = \mathbf75% )

4. Challenge â Cathedral Beam
First find AMA from efficiency:
( 0.75 = \fracAMA12 \Rightarrow AMA = 9 )
Then ( AMA = \fracF_\textoutF_\textin \Rightarrow 9 = \frac14,000 , \textNF_\textin )
( F_\textin = \frac14,0009 \approx \mathbf1,556 , N ) (about 350 lbs) Efficiency tells you how well a machine converts

Efficiency tells you how well a machine converts input work to output work.

Formula: [ \textEfficiency = \frac\textoutput work\textinput work \times 100% ]

Since work = force Ã distance: [ \textEfficiency = \fracAMAIMA \times 100% ] Problem 7: Using the crowbar from Problem 1 (AMA = 4

No real machine is 100% efficient (friction always wastes some energy).

Problem 7: Using the crowbar from Problem 1 (AMA = 4.0), if the IMA of the lever is 5.0, what is the efficiency?

Problem 8: A worker does 500 J of input work on a pulley system. The pulley system does 400 J of output work lifting a box. What is the efficiency? what is the efficiency?

Problem 9 (Critical Thinking): A machine has an IMA of 6.0 and an AMA of 6.0. Is this possible in the real world?

Mechanical advantage tells you how many times a machine multiplies your input force. There are two types:

Ideal Mechanical Advantage (IMA): Assumes no friction (theoretical maximum).