BICEPS and TRICEPS
BICEPS and TRICEPS
Which One Is Stronger??
Objective:
The student will calculate speed, momentum, acceleration and force in the human arm.
Pre-lab:
1. Review the terms extend, flex, biceps brachii and triceps brachii.
Biceps brachii - hold the long side of the book in the dominant hand. Let the book hang at your side with your arm fully extended downward. Raise the book by flexing (bending) your arm from the elbow toward your face as far as you can. Lower the book by fully extending the arm downward.
Triceps brachii - hold the long side of the book in the dominant hand and flex (bend) your arm at the elbow bringing the elbow all of the way up to the top of your head. The book is now touching your back. Push the book straight up into the air until the arm is fully extended; then return the lower arm and book next to your back again. (Just as if you were pushing up dumbbells)
Hypothesis: Make a statement about the strength of the biceps and triceps muscle. Which one do you think is stronger?
____________________________________________________________________
Review formulas on motion that can be used to prove your hypothesis. Write these formulas in
each box. Write the units for expression of each formula underneath the box.
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Materials: Stop watch or clock with second hand, metric ruler, scale, textbook
Procedures:
The students will perform an experiment to test their hypothesis.
1. Work with a partner.
Biceps brachii – Decide how you and your partner will measure the distance the book travels when bending the lower arm. Measure the distance in centimeters (cm). Raise and lower the book at least 5 times. Measure time in seconds (s). Repeat this exercise for 3 trials. Record each student’s measurements in the data table. Hint: Switch partners between each trial.
Triceps brachii - Repeat the same instructions for the triceps brachii.
3. Each student uses their data to calculate speed, momentum, acceleration and
force using the formulas from the prior discussion in the “boxes”.
Flexing Biceps
| |Time |Distance |Speed=d/t |Momentum |Acceleration |Force |
| | | | |p=mv |A=ρv/t |F=ma |
|Trial one | | | | | | |
| | | | | | | |
|Trial two | | | | | | |
| | | | | | | |
|Trial three | | | | | | |
| | | | | | | |
Extending Triceps
| |Time |Distance |Speed=d/t |Momentum |Acceleration |Force |
| | | | |p=mv |A=ρv/t |F=ma |
|Trial one | | | | | | |
| | | | | | | |
|Trial two | | | | | | |
| | | | | | | |
|Trial three | | | | | | |
| | | | | | | |
Conclusion:
1. Was your hypothesis verified?
2. Justify the use of the formula that best applied to your hypothesis. (speed, momentum, acceleration or force?)
3. Can the same formula used to calculate speed be used to calculate velocity in this experiment? Explain.
4. Write a rational explaining your use of technique in contracting either the biceps or triceps muscle.
5. Write a rational explaining which of Newton’s three laws directly apply to this activity.
Practice Problems:
1. What is the acceleration of a girl on a surfboard if the force on the girl is 20N and the mass of the girl and surfboard is 72kg?
2. You drive a car for 2.0 h at 40 km/h, then for another 2.0 h at 60 km/h. a. What is your average speed?
b. Do you get the same answer if you drive 100 km at each of the two speeds?
3. An object sits on a frictionless surface. There is a 16 N force being applied to an
object and its acceleration is at 2 m/s/s. What is its mass?
Critical Thinking Skills
4. Read Newton’s Second Law. If the book’s acceleration were twice the amount used in the activity what would be the force? If the book’s acceleration was half the amount used in the activity what would be the force? What is the relationship between force and acceleration?
5. Describe the motion of lifting foam weights under water. Use the terms velocity, acceleration, force, and friction in your answer.
6. Discuss how you and your partner would re-design the lab activity to more accurately test the strength of muscles. Experiment with this new design and compare the numbers.
7. See page 270 in your textbook and the explanation of force being measured in Newton. Would the equivalent of 1N = .225 lb. or 1 lb = 4.448N apply to this lab?
Weigh your text, make conversions, and consider the formula for force and justify your answer.
8. Design a sports activity using two of the motion and force formulas to measure performance. Write the procedures for implementing this activity. Experiment with this activity and record results
Marybeth Gardner
FBISD Science specialist
2007
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[pic]
Which muscle is stronger,
the biceps or triceps?
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