FOT Semester Exam

Wednesday, May 25 - Free Response

Thursday, May 26 - Multiple choice

You must have a calculator for free response – NO SHARING and NO CELL PHONES

Semester Exam is worth 1/6th of your FOT final grade

REVIEW

For each problem:1) List all given information2) Sketch a diagram if required3) Write the applicable formula and rearrange if necessary4) Substitute the known values and solve for unknown5) Show correct units6) Circle/ Box the correct answer.

1. You carry a basket of laundry weighing 25 pounds up a flight of stairs with a total height of 9 feet. How much work did you do (keep all units)?

REVIEW

W = ?F = 25 lbsD = 9 ft

List Given Information

Write FormulaW = F x D

Substitute Values

W = 25 lbs x 9 ft

Solve

W = 225 ft-lbs

Review

2010 Hummer H2• Output = 320 miles• Input = 32 gallons• Efficiency = ?

2010 Toyota Prius• Output = 500 miles• Input = 10 gallons• Efficiency = ?

Eff=Wo / WiEff= 500 mls / 10 gal

Eff = 50 mpg

Eff=Wo / WiEff= 320 miles / 32 gal

Eff = 10 mpg

3. A hot air balloon carries 300 lbs cargo, 250 lbs human, and 450 lbs materials up a distance of 2,000 feet. How much work did the balloon do (keep all units)?

Review

W = ?F = 300 lbs+ 250 lbs +450lbsD = 2,000 ft

List Given Information

Write Formula

W = F x D

Substitute Values

W = 1,000 lbs x 2,000 ft

Solve

W = 2,000,000 ft-lbs

Review

4. A physical therapy doctor told his 200-lb patient to do 30,000 ft-lbs of work each day to rehabilitate his leg. The patient decides to climb a hill to perform this work. How high does the patient need to climb in order to meet his goal?

W = 30,000 ft-lbsF = 200 lbsD = ??

List Given Information

Write Formula

W = F x D

Substitute Values

30,000 ft-lbs 200 lbs x DSolve

lbs

lbsftD

200

000,30

D = 150 ft

Review

5. A 1st class lever is used to lift a fallen log that weighs 120 lbs. The log is located 3 ft from the fulcrum. A child can apply a 12 lb force on the other side. How far from the fulcrum should the child stand?

120 lbs

3 ft. DF = ?

F = 12lbs

L = 120 lbsDL = 3 ftF = 12 lbsDF = ???

List Given Information

Write Equation

Sketch Diagram

LxDL=FxDFSubstitute and Solve

120lbs x 3 ft = 12 lbs x DFDF = 30 ft

Review

6. A gardener is capable of applying 50 lbs to lift a wheelbarrow. His hands are placed 4 ft from the axle. If the dirt is located 2 ft from the axle, how much dirt can the gardener carry?

2ft

DF = 4ft

F = 50lbs

L = ?DL = 2 ftF = 50 lbsDF = 4ft

List Given Information

Write Equation

Sketch Diagram

LxDL=FxDFSubstitute and Solve

L x 2 ft = 50 lbs x 4ftL = 100lbs

Review

6. A 3rd class mechanical lever is used to remove snow without damaging the pavement. The machine can apply 600 lbs of fore. The distance from the load to the fulcrum is 8 ft. The distance to the applied force is 4 ft. What is the maximum amount of snow removed, what is the mechanical advantage?

DF= 4ft

DL = 8ft

F = 600lbs

L = ?DL = 8 ftF = 600 lbsDF = 4ft

List Given Information

Write Equation

Sketch Diagram

LxDL=FxDFSubstitute and Solve

L x 8 ft = 600 lbs x 4ftL = 300lbs M.A. =1/2

Review

8. A fixed pulley system is used to lift a bucket from a well. How many pounds are required to lift 60 lbs of water.

MA = 1L = 60 lbsF = ??

List Given Information

Write Equation

Sketch Diagram

Substitute and Solve1 = 60 lbs / F

F

LMA

F = 60 lbs

Review

9. A movable pulley system is used to lift a bucket from a well. How many pounds are required to lift 60 lbs of water.

MA = 2L = 60 lbsF = ??

List Given Information

Write Equation

Sketch Diagram

Substitute and Solve2 = 60 lbs / F

L = 60lbsF

LMA

F = 30 lbs

Review

10.A block and tackle pulley system is used to lift a bucket from a well. How many pounds are required to lift 60 lbs of water.

MA = 3L = 60 lbsF = ??

List Given Information

Write Equation

Sketch Diagram

Substitute and Solve3 = 60 lbs / F

F

LMA

F = 20 lbs

11. A Lexus RX400h hydrid carries a 288-volt battery stystem. The batteries power electric motors that use 44.8 kW of power. What is the current traveling through this high voltage current. What is the resistance?

REVIEW

P = 44,800 WI = ?V = 288 V

List Given Information

Write FormulaP = I x V

V = 288V

I = ?

-

+P = 44,800 W

44,800 W = I x 288 VI = 156 A

11. A Lexus RX400h hydrid carries a 288-volt battery stystem. The batteries power electric motors that use 44.8 kW of power. What is the current traveling through this high voltage current. What is the resistance?

REVIEW

V = 288 VI = 156 AR = ??

List Given Information

Write FormulaV = I x R

V = 288V

I = ?

-

+P = 44,800 W

288 V = 156 A x RI = 1.85 Ohm

U3e-L3

12. Use the Schematic to solve for RA, RB, and RT

4 W

12W 10 W

40 W

21

111

RRRA

12

1

4

11

AR 3

1

12

41

AR3AR

10

1

40

11

BR 10

1

40

11

BR 8

1

40

51

BR8BR

U3e-L3

12. Use the Schematic to solve for RA, RB, and RT

4 W

12W 10 W

40 W

83 BAT RRR

11TR

U3e-L3

13. Use the Schematic to find the total resistance of the circuit

1.5W7 W

6 W

21

111

RRRP

7

1

6

11

PR 42

13

42

6

42

71

PR23.3PR

21 RRRT 73.423.35.1 TR

U3e-L3

14. Use the Schematic to solve for R

4 W

120V R=? 40 W

5 Amp

V = 120VI = 5 AR = ??V = IxR

List Given Information

120 V = 5A x RR = 24 Ohm

U3e-L3

14. Use the Schematic to solve for R

4 W

120V R=? 40 W

5 Amp

40

11

24

1

R 40

1

24

11

R 120

2

120

3

120

51

R

R = 60 Ohm

U3f – L3

15.A sample of hydrogen gas is compressed from 300 cm3 to 2 cm3. Its pressure is now 5 psi. What was the original pressure of the helium?

Step 1: Write given information

P1 = ?

V1 = 300 cm3

P2 = 5 psi

V2 = 2 cm3

Step 2: Write the formula and solve

P1V1 = P2V2

P1 x (300 cm3) = 5 psi x (2 cm3)

P1 x (300 cm3) = 10 psi*cm3

300 cm3 300 cm3

P1 = 0.0333 psi

U3f – L3

16. The surface of a concrete block that touches the ground is 1.5 ft^2. What is the pressure on the ground if the block weighs 25 lbs

Step 1: Write given information

P = ?

F = 25 lbs

A= 1.5 ft2

Step 2: Write the formula and solve

P=F/A

P = 25 lbs/1.5 ft^2

P = 16.7 psf

U3f – L3

17. What would hurt more: 25 lbs against 1 square inch of your body or 5 pounds against 0.01 square inches

Step 1: Write given information

P1 = ? P2 = ?

F1 = 25 lbs F2 = 5 lbs

A1= 1 in2 A2= 0.1 in2

Step 2: Write the formula and solve

P1=F1/A1 P2 = F2/A2

P1= 25 lbs/1 in^2 P2 = 5 lbs/0.01 in^2

P1 = 25 psi P2 = 500 psi

U3f – L3

The diagram below illustrates how hydraulic brakes in a car work. The pedal must be pressed with a force of 10 lbs. The surface area of the piston connected to the pedal is 1 square inch. If the surface area of the piston connected to the other end of the brake line is 2.5 square inch, what is the force applied to that piston?

P1 = P2

Problem 18

P1 = F1 / A1 P2 = F2 / A2

U3f – L3

Problems

Solution:Step 1: Write given information

P1 = ? P2 = ?

F1 = 10 lbs. F2 = ?

A1 = 1 in2 A2 = 2.5 in2

Step 2: Write the formula and solve for the unknowns

P1 = F1 / A1

P1 = (10 lbs) / (1 in2)

P1 = 10 psi

P1 = P2 = 10 psi

F2 = 10 psi x 2.5 in2 = 25 lbs.P2 = F2 / A2 F2 = P2 x A2