# Tredyffrin/Easttown School District / Overview

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Work and Power Lab NAME ___________________________

How Fast Can You Do Work?

I. PURPOSE: In this activity, we will experience the concepts of Work and Power using simple classroom materials. Please complete the following activities in your group.

II. MATERIALS:Spring Scale, Scale, Mass, Meter Stick(s), Stopwatch, Calculator

III. DEFINE the following, include the equation used to calculate the term if it applies.

1) Work: ________________________________________________________

2) Power: ________________________________________________________

3) Newton: _______________________________________________________

4) Joule: _________________________________________________________

5) Watts: _________________________________________________________

6) Horsepower:____________________________________________________

IV. PROCEDURE ONE

Let the FORCE Be With You…

Measured Force

1. Select an object (wood block, etc.) and use the Spring Scale to “lift” the object.

Determine how many Newton’s your object weighs.

____________ N

Calculated Force

2. Determine the mass of the object using a triple beam balance: ____________ g

3. Convert the mass of the object to kilograms. ____________ kg

4. Calculate the Force (weight) of the object using Newton’s 2nd Law:

Force = mass x acceleration of gravity

Force (weight) = ____________ kg x ___________ m/s2 = ____________ N

5. Compare your measured Force (see #1) with the calculated Force (#4). Analyze any similarities or differences you see.

__________________________________________________________________________

__________________________________________________________________________

__________________________________________________________________________

V. PROCEDURE TWO

How Fast Can You Do Work?

PART A: ROLL-UP (WRISTS AND FOREARMS)

1) Measure and record the mass (kg) of the object that is to be lifted.

2) Attach a mass to the end of a string.

3) Measure and record the distance (m) from the hanging mass to the top of the string where the string goes into the dowel rod.

4) Measure and record the time (s) as to how quickly you can raise the mass by rolling the string onto the dowel rod lifting the mass as you twist your hands.

5) Calculate the force (N), work (J), power (W) and horsepower (hp) that was produced from this activity and record your data in the table below.

|Force (N) = kgm/s2 |F = m x a |

|Work (J) = Nm |W = F x d |

|Power (W) = J/s or Nm/s |P = [pic] |

|Horsepower |hp = [pic] |

|(1 hp = 746 W) | |

|Mass (kg) | |

|Distance (m) | |

|Time (s) | |

PART B: PUSH-UPS (CHEST AND ARMS)

1) In an “up/ready push-up position”, place your hands on the scale to determine the amount of your body’s mass you will be pushing. Record the data in kg in the data table below.

2) Measure the distance (m) from the floor to the front of your body (chest).

a. You can do as many push-ups as you like (5 push-up minimum). REMEMBER TO MULTIPLY THE DISTANCE BY THE NUMBER OF PUSH-UPS YOU DO IN ORDER TO GET THE TOTAL DISTANCE IN METERS. RECORD THE TOTAL DISTANCE IN YOUR DATA TABLE.

3) Measure and record the amount of time (s) it takes to perform the 10 push-ups.

4) Calculate the force (N), work (J), power (W) and horsepower (hp) that was produced from this activity and record your data in the table below.

|Mass (kg) | |

|Distance (m) | |

|Time (s) | |

|Force (N) = kgm/s2 |F = m x a |

|Work (J) = Nm |W = F x d |

|Power (W) = J/s or Nm/s |P = [pic] |

|Horsepower |hp = [pic] |

|(1 hp = 746 W) | |

PART C: CURLS (FRONT OF UPPER ARMS/BICEPS)

1. Use the scale to measure and record the mass (kg) of your object.

2. Hold the weight in your hand that you will be using for this activity. Let your arm hang down in a relaxed, ready position.

3. Measure the distance(m) from this starting position to its final position as you curl your arm upward, stopping at your shoulder. MULTIPLY THE DISTANCE OF ONE ARM CURL AND MULTIPLY IT BY 10 TO GET THE TOTAL DISTANCE IN METERS. RECORD THE TOTAL DISTANCE IN YOUR DATA TABLE.

4. You will be doing 10 arm curls in as little time as possible. Measure and record the total time (s) it takes to perform the 10 arm curls.

5. Calculate the force (N), work (J), power (W) and horsepower (hp) that was produced from this activity and record your data in the table below.

|Mass (kg) | |

|Distance (m) | |

|Time (s) | |

|Force (N) = kgm/s2 |F = m x a |

|Work (J) = Nm |W = F x d |

|Power (W) = J/s or Nm/s |P = [pic] |

|Horsepower |hp = [pic] |

|(1 hp = 746 W) | |

PART D: STAIR RUN (LEGS)

1. Use the scale to measure your weight in pounds, then convert to kilograms. Record the total mass (kg) in the data table below.

2. Determine the distance from the bottom of first floor to the top of the second floor.

3. To do this, measure the height of each step and count the number of steps between the first and second floor.

4. Record the total distance (m) in your data table.

5. With a stopwatch, measure and record the time (s) it takes you to get from the first floor to the second floor.

6. Calculate the force (N), work (J), power (W) and horsepower (hp) that was produced from this activity and record your data in the table below.

|Force (N) = kgm/s2 |F = m x a |

|Work (J) = Nm |W = F x d |

|Power (W) = J/s or Nm/s |P = [pic] |

|Horsepower |hp = [pic] |

|(1 hp = 746 W) | |

|Mass (kg) | |

|Distance (m) | |

|Time (s) | |

VI. ANALYSIS QUESTIONS:

ANSWER THE FOLLOWING QUESTIONS IN COMPLETE SENTENCES.

1) Identify the two variables that affect work?

2) Which activity required the most work? Explain this using the two variables that affect work from answer #1.

3) Which activity produced the most power? Explain why.

4) If you wanted to produce more power, what could you do to maximize power?

5) Would you be doing any more work by going up the stairs twice as fast? Explain.

6) This lab should have led you to a point of better understanding of work and power. It is now your chance to pull it all together by writing a well written, thoughtful paragraph about how the terms below are all interrelated. It should make logical sense and include all of the following terms. (Please write your paragraph on a separate piece of paper and attach to the lab packet.)

|Work |Power |Joule |Newton meter |

|Kgm/s2 |Joule / second |Newton |Horsepower |

|Force |Distance |Time |Watts |

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