Brake Work Example 21

ACT Work Keys Level: 4
NATEF Task(s): V.B.1

Problem:

Formulas:
D_o = Distance Output
D_i = Distance Input
F_o = Force Output
F_i = Force Input
Distance or Force Transformance = F_i(Di) = D_o(F_o)
B = Bore = D = diameter
r = D(½) or Bore(½)
r² = r · r
p = 3.14159
square inches = r²(p)
= pounds per square inch (psi)

1. Describe the output force of a system if an input force of 75 lbs is exerted on a 1 sq. inch input piston and the output piston is .5 sq. inch. (Show your work.)
2. What is the system pressure in the above example?
3. Describe the output force of a system if an input force of 125 lbs is exerted on a 1 sq. inch input piston and the output piston is 7 sq. inches. (Show your work.)
4. What is the system pressure in the above example?
5. Describe the output force of a system if an input force of 125 lbs is exerted on a 1 sq. inch input piston and the output piston is .75 sq. inch. (Show your work.)
6. What is the system pressure in the above example?

Solution:

1. = 75 psi = 75 psi (.5") = 37.5 lbs of force

2. 75 psi

3. = 125 psi = 125 psi (7") = 875 lbs of force

4. 125 psi

5. = 125 psi = 93.75 lbs of force

6. 125 psi