Advertisement - Members don't see this ad
Working through EK Physics 101 passages, in particular Test 3A, question 46:
"Many bed-side patient lift assists use hydraulics to provide a mechanical advantage. What force should be applied, and to which piston, to provide 700N lifting assistance? Piston A has a diameter of 4cm, and piston B has a diameter of 1m"
A) 56N to piston A
B) 28N to piston A
C) 56N to piston B
D) 28N to piston B
Seems straight forward enough but I not getting the indicated answer from the solutions (B). I get that according pascals principal you will apply the force to the smaller area piston, A in this case (Eliminating solutions C, and D).
You are just then left to solve via F1/A1=F2/A2. I don't get any of the answers above, I end up with F1=((700N)*(0.02^2))/(0.5^2), which doesn't give any of the above.
The solution guide changes Area to diameter getting F1/0.04=700/1 --> 28N.
Can anyone explain how this makes sense. Maybe I'm just missing something straight forward but I don't get how you can just sub diameter in for area (considering area of a circle increases exponentially).
Thanks in advance
"Many bed-side patient lift assists use hydraulics to provide a mechanical advantage. What force should be applied, and to which piston, to provide 700N lifting assistance? Piston A has a diameter of 4cm, and piston B has a diameter of 1m"
A) 56N to piston A
B) 28N to piston A
C) 56N to piston B
D) 28N to piston B
Seems straight forward enough but I not getting the indicated answer from the solutions (B). I get that according pascals principal you will apply the force to the smaller area piston, A in this case (Eliminating solutions C, and D).
You are just then left to solve via F1/A1=F2/A2. I don't get any of the answers above, I end up with F1=((700N)*(0.02^2))/(0.5^2), which doesn't give any of the above.
The solution guide changes Area to diameter getting F1/0.04=700/1 --> 28N.
Can anyone explain how this makes sense. Maybe I'm just missing something straight forward but I don't get how you can just sub diameter in for area (considering area of a circle increases exponentially).
Thanks in advance
