Lab #14: Sudden Stops Hurt-Newton's First Law - NNM-Science

Lab #14: Sudden Stops Hurt-Newton’s First Law 

In this lab, you will perform experiments about inertia and Newton’s First Law in terms of car crashes. 

Objectives 

You will: 

� Describe situations with zero acceleration, other than objects at rest. 

� Be able to explain the role of Newton’s first law and inertia in car crashes. 

� Be able to explain the importance of seat belts in terms of physics concepts. 

Background 

Newton’s first law describes the motion and acceleration of objects. There are two parts to the 

law. The first part says that an object at rest will stay at rest. The second part says that an 

object in motion will stay in motion. Both parts of the law have an addition that say “unless acted upon by an unbalanced force.” 

Tying together what we have learned so far about velocity and acceleration, look at the diagram to the right. Another way of 

looking at this law is to say that objects will not accelerate unless they are acted on by unbalanced forces. 

Pre-Lab Questions 

1. Can an object in motion have an acceleration of zero? If so, how? 

2. In a car crash, there are two collisions. The first one is when the car runs into the other car. What do you think the "second 

collision" is? (Hint: It's the one that hurts) 

3. Refer to the picture to the right. The car is about to run into the wall. Make a 

prediction about what will happen to the car, and what will happen to the person 

in the car. PREDICTION: The car will _______________________, and the person in the car will _________________________. 

Setup: 

You will make observations to test your 

prediction from above. Set up a ramp 

and a "wall" as shown: 

Procedure: 

1. Place a penny on the top of a toy car, and place the car's front wheels directly behind the 10 cm line. 

2. Let the car go. Record the distance the penny flies from the cart. (If the penny is hitting the book “wall”, adjust the height of the 

wall so that the penny can fly freely from the car). Repeat two more times from 10 cm. 

3. Repeat steps 1-2 from 20 cm, 30cm, and 40cm, and calculate averages for these four distances. Graph your findings. 

4. Using your graph, make a prediction about how far the cube will fly if the car is released from 55cm. Record in the table below. 

5. Release the car from 55 cm and record the actual distance in the table below. 

Data 

Distance Up 

Ramp (cm) 

10 

20 

30 

40 

Book 

s 

Distance Penny is Thrown (cm) Average 

Trial 1 Trial 2 Trial 3 distance (cm) 

Wooden Board 

Qualitative Observations 

Book (This is the "wall") 

55** Distance prediction from graph: ___________ Actual distance from trial: _________________ 

Reading in lab 14 taken from http://www.glenbrook.k12.il.us/GBSSCI/PHYS/CLASS/newtlaws/u2l1a.html, reading in lab 16 taken from 

http://id.mind.net/~zona/mstm/physics/mechanics/forces/newton/newtonLaw2.html , lab 21 adapted from The Book of Phyz by Dean Baird , labs 

19 and 20 Adapted from http://alex.state.al.us/lesson_view.php?id=6183 Page 1

Questions (separate piece of paper, please!) 

1. Was your prediction about the car in the cartoon verified (proven true) by your experiments? Explain. 

2. This lab involves the part of Newton’s First Law that says an object in motion will stay in motion unless acted upon by an 

unbalanced force. Two objects are in motion in this lab. What are they? 

3. What is the unbalanced force acting in this lab? 

4. What object stays in motion, though the other object has been stopped by the unbalanced force? 

5. When the penny is on the car, it travels in the same direction as the cart. When the penny is thrown from the car, in what 

direction does it go? Why does the penny go in that direction? 

6. Explain how seat belts work in terms of Newton’s first law and use the words “inertia” and “unbalanced force” in your answer. 

Lab #15: Whiplash or Broken Nose-Newton’s 1st Law 

In this lab, you will simulate several car collisions and make predictions about which direction the 

“passengers” (metal cubes) in each will move. 

Background 

To summarize, Newton’s first law says that an object at rest will stay at rest, and an object in motion will stay in motion unless acted 

upon by an unbalanced force. In Lab #14, you found that objects in motion (the car and the “passenger”), continue in motion, unless 

acted upon by an unbalanced force (the book). The car is acted on by the unbalanced force, but the passenger is not, which is why it 

continues moving forward. The passenger in the car is said to have inertia, which is a tendency for an object to do what it is already 

doing. Many times, Newton’s first law can be summarized with just this one word: inertia. 

Pre-lab Question 

Observe the demonstration with the hard-boiled and raw egg. Explain what you see in terms of inertia. 

Procedure 

Front of Carts 

1. Set up your ramp as it was in lab #14, minus the books 

at the bottom. You will be using dynamics carts and 

cubes as passengers in this lab. 

2. Put one cart at the base of the ramp, 20 cm 

from the ramp, as shown in the diagram below. 

The front of the car should be facing away from 

the ramp. Place a metal cube on that cart. This is the resting car. 

3. Put the other cart on the ramp at the 20 cm mark, and put one 

cube in the middle of that cart. This is the crashing car. The front 

of this cart should be facing toward the bottom of the ramp. 

4. You should now have the resting cart set up to be rear-ended by the crashing cart. Let the crashing cart go and record what 

direction the pennies on both carts move. 

Prediction: Using knowledge gained in lab #14, predict which direction you expect the pennies on each car to go. Refer to 

specific directions like “toward the ramp” and “away from the ramp.” The penny on the resting car will _____________________ 

_________________________, and the penny on the crashing car will__________________________________________________. 

Data 

Trial Number Direction of Motion of Resting Cart's 

Penny 

1 

2 

3 

Back of carts 



19 and 20 Adapted from http://alex.state.al.us/lesson_view.php?id=6183 Page 2 

20 cm 

Direction of Motion of Crashing Cart's 

Penny

Questions (on a separate piece of paper): 

1. Was your prediction verified? Explain. 

2. If the penny on the resting cart had been the driver of a car that was rear-ended, would the 

driver have more likely suffered whiplash or a broken nose? (Whiplash is when your head snaps 

backward). 

3. If you were a passenger standing in the aisle of a bus that suddenly lurched forward, how would 

your body react? Why? 

4. To dislodge ketchup from the bottom of a ketchup bottle, it is often turned upside down and 

thrust downward at high speeds and stopped suddenly. Explain why this is done using the 

following terms: inertia, unbalanced force. 

5. The truck pictured to the right has a sturdy wall behind the driver's cab. What is the purpose of 

this wall? Explain in terms of Newton’s First Law. 

Lab #16: Newton’s 2nd Law: Calculating Force 

Objectives: 

You will: 

� Measure the theoretical force of a rubber band Hot Wheels launcher directly by using a force meter. 

� Calculate the actual force of a rubber band Hot Wheels launcher indirectly through calculation. 

Background: 

Newton’s second law describes how force, mass, and acceleration are related. First, this law states that if you do place a force on an 

object, it will accelerate, i.e., change its velocity, and it will change its velocity in the direction of the force. It accelerates in the 

direction that you push it. 

Secondly, this acceleration is directly proportional to the force. For example, if you are pushing on an object, causing it to accelerate, 

and then you push, say, three times harder, the acceleration will be three times greater. If you push twice as hard, it accelerates 

twice as much. 

Thirdly, this acceleration is inversely proportional to the mass of the object. For example, if you are pushing equally on two objects, 

and one of the objects has five times more mass than the other, it will accelerate at one fifth the acceleration of the other. If it gets 

twice the mass, it accelerates half as much. 

Pre-lab Question: 

Complete the following table, after reading the background above: 

Net Force Mass 

Acceleration 

(N) 

(kg) 

(m/s/s) 

1. 10 2 

2. 20 2 

3. 20 4 

4. 2 5 

5. 10 10 

Procedure: Direct Measurement of Force 

1. Open the file “16-Newton2Law” from the App$ server in the Science/Logger Pro folder. 

2. Attach the force sensor to the rubber band on the launcher, and pull it back to the first line on the board. Hold it as steady as you 

can, and have someone record the force from the force meter in Logger Pro. 

Force measured from force meter: _______________ 




Procedure: Indirect Measurement of Force 

1. Take a Hot Wheels car and practice releasing it with the rubber band launcher. If the launcher seems to not be hitting the car 

squarely or consistently, attach card stock to the back of the car to make a more consistent surface for the launcher to hit. Make 

sure the card stock does not rub against the tires or otherwise negatively affect the movement of the car. 

2. Measure and record the mass of the car in grams in the table below. Convert that mass to kilograms. 

3. Click collect on Logger pro, and pull the binder clip with rubber band back to the first screw. Let the car go, and allow Logger Pro 

to calculate the acceleration from the two photogates. Record the acceleration in the table below. 

4. Calculate the Force in Newtons of the rubber band launcher (see the formula above). 

5. Repeat steps 2-3 two more times. 

Trial # 

1 

2 

3 

Mass of Car (g) Mass of Car (kg) Acceleration from Gate One to Gate Two 

(m/s/s) 

Average force (N): 

Questions (on a separate piece of paper, please!) 

1. The direct and indirect measurements of force were different. Brainstorm and explain 2 reasons why this might be. 

2. If you were to double the mass of the car, how would you expect its acceleration to change? 

3. If you were to double the mass of the car, how would you expect the force of the launcher to change? 

Calculated Force (N) 

Lab #17: Newton’s 2nd Law: Relationship between mass & acceleration 

Objectives: 

You will: 

� Describe the relationship between mass and acceleration, when the force is kept constant. 

Pre-Lab Questions: 

Manipulated variable: ___________________________ Responding variable: ______________________ 

Controlled variables (2): ___________________________________________________________________ 

Hypothesis: If ___________________________________________________________________________________________, then 

____________________________________________________________________________________________________, because 

___________________________________________________________________________________________________________. 

Make a prediction about what the graph to the left will look like (sketch the shape of 

the graph as a prediction): 

Procedure: 

1. Open the file “17-Newton2Law” from the App$ server in the Science/Logger Pro 

folder. 

2. Measure and record the mass of a car in grams. Convert that mass to kilograms. 

3. Put the car in the launcher with the clip pulled back to the first screw, and make 

sure the car is blocking the first photogate (red light should be on). Click collect on 

Logger Pro, and let the car go. Record the acceleration in the table below. 

4. Repeat steps 2-3 two more times, being sure to pull the rubber band back to the 

Mass of Car 

same screw each time. 

5. Add 2 pennies to the top of the car and secure them with tape. Repeat steps 2-4. Continue adding 2 pennies until you reach 10 

pennies. Calculate the average acceleration for each mass. 



19 and 20 Adapted from http://alex.state.al.us/lesson_view.php?id=6183 Page 4 

Acceleration 

The Effect of Mass on the Acceleration of a Toy Car

Mass of car 

(g) 

Mass of car 

(kg) 

Trial # Acceleration from Gate One to Gate 

Two (m/s/s) 

1 

2 

3 

1 

2 

3 

1 

2 

3 

1 

2 

3 

1 

2 

3 

1 

2 

3 

Average Acceleration (m/s/s) 

Questions (answer on a separate piece of paper, please!) 

1. Go back to your graph prediction. Roughly plot your data points from the table above onto that graph. Was your prediction 

correct? 

2. Describe the relationship between mass and acceleration of a toy car. Is it direct, inverse, or neither? Explain. 

3. If you were to double the mass of your car, what would you expect to happen to the acceleration? 

4. If you were to half the mass of your car, what would you expect to happen to the acceleration? 

5. Write a conclusion for this lab. 

Lab #18: Newton’s 2nd Law: Relationship between force & acceleration 

Objectives: 

You will 

� Explain the relationship between acceleration and force, if mass is kept constant 

Procedure: 

1. Open the file “18-Newton2Law” from the App$ server in the Science/Logger Pro folder. 

2. Measure and record the mass of a car in grams in the table below. Convert that mass to kilograms. 

3. Click collect on Logger pro, and pull the binder clip with rubber band back to the first screw. Let the car go, and allow Logger Pro 

to calculate the acceleration from the two photogates. Record the acceleration and force in the table below. 


5. Pull the rubber band back to the second screw and then the third screw, and repeat steps 3-4 three times. 

6. Calculate the force at each point using Newton’s 2 nd law formula. 

7. Print your graph. 




Data: 

Mass of car (g): Mass of car (kg): 

Force of Trial # Acceleration from Gate One to Gate Two 

Launcher (N) 

1 

2 

3 

1 

2 

3 

1 

2 

3 

(m/s/s) 

Average Acceleration (m/s/s) 

Questions (on a separate piece of paper, please!) 

1. Describe the relationship between force and acceleration of a toy car. Is it direct, inverse, or neither? Explain. 

2. If you were to double the force acting on your car, what would you expect to happen to the acceleration? 

3. If you were to half the force of your car, what would you expect to happen to the acceleration? 

Lab #19:Newton’s 3rd Law: I Should’ve Seen it Coming! 

Newton’s 3 rd law states that for every action there is an equal and opposite reaction. While this is easy to 

repeat and memorize, it isn’t so easy to understand and believe. For example, this means that when you push against a table, the 

table pushes back on you with the same amount of force. (Think about that…it is easy to recite, but harder to understand). In this 

lab, you will begin to investigate Newton’s 3 rd Law by creating single-car accidents by running a dynamics cart into a wall. 

Procedure: Part 1 

1. Place the ramp 50 cm from a wall. Roll a car down the plane, releasing it from the 30 cm mark each time. 

2. Measure and record the distance the car bounces. Move the ramp out of the way if necessary to allow the cart to roll freely after 

hitting the wall. 


4. Repeat the experiment 5 times, adding 50 grams of mass to the cart each time. Calculate the average distance for each test. 


Manipulated variable: ___________________________ Responding variable: ______________________ 

Controlled variables (2): ___________________________________________________________________ 

Hypothesis: If ___________________________________________________________________________________________, then 

____________________________________________________________________________________________________, because 

___________________________________________________________________________________________________________. 

Grams on Car Car’s Distance (cm) Average Car distance 

(cm) 

Trial 1 Trial 2 Trial 3 

0 

50 

100 

150 

200 

250 




Questions 

1. Newton’s 3 rd Law states that for every action, there is an equal and opposite reaction. What is the “action” in this lab? What is 

the “equal and opposite reaction?” 

2. Do you agree that the resulting action was “equal”? Explain how you came to this conclusion. 

3. Do you agree that the resulting action was “opposite? Explain how you came to this conclusion. 

4. Graph your results from this lab. It should be a line graph with “grams on car” on the x-axis and “distance traveled” on the yaxis. 

Be sure to label your graphs appropriately. (I have graph paper if you need it). 

Lab #20:Newton’s 3rd Law: Man, that’s gotta hurt! 

In this lab, you will continue to investigate this relationship, by creating car collisions. You should be 

interested in observing what happens to the ramp cart, rather than the cart that is being run into. 

Procedure: Part 1: Change in ramp cart’s mass 

1. Place one cart 60 cm from the end of the ramp, facing away from the ramp. Place the other cart at the 40 cm mark of the 

ramp so that it will hit the first cart when you let go. 

2. Let go, and make sure at least one person is watching to observe the exact point of impact, because you will need to make 

some measurements from the point of impact. What happened to the ramp cart? Measure the distance each car moved 

from the point of impact and the direction of movement. Record your observations in the data table. 

3. Repeat steps 1 and 2 two more times. 

4. Repeat steps 1-3, each time adding 50 grams to the ramp cart. Stop when you reach 250 grams. 


I expect the ramp cart to move in the following direction (describe):_____________________________________________________ 

This is what I expect to see in the distance traveled by the ramp cart as I add more weight:_________________________________ 

I expect the resting car to move in the following direction (describe): ________________________________________________ 

This is what I expect to see in the distance traveled by the resting cart as I add more weight to the ramp car: 

__________________________________________________________________________________________ 

What is the manipulated variable? _________________________ 

Ramp Cart Mass 

(g) 

0 

50 

100 

150 

200 

250 

Ramp Cart’s Direction (away 

from or toward point of impact) 

Ramp Cart’s 

Distance (cm) 

Resting Cart’s Direction (away from 

or toward point of impact) 

Resting Cart’s 

Distance (cm) 

Procedure: Part 2 (Change in resting cart’s mass) 

5. Now, remove the weights from the ramp cart and add them one at a time to the cart at the bottom of the ramp following 

the same procedure above. Again, record your observations and measurements. 




Grams on Resting 

Car 

0 

50 

100 

150 

200 

250 

Ramp Car’s Direction Ramp Car’s 

Distance (cm) 

Resting Car’s Direction Resting Car’s 

Distance (cm) 

Questions 

1. Newton’s 3 rd Law states that for every action, there is an equal and opposite reaction. What is the “action” in this lab? 

__________________What is the “equal and opposite reaction?” _____________________________ 

2. Do you agree that the resulting action was “equal”? Explain how you came to this conclusion. 

3. Do you agree that the resulting action was “opposite? Explain how you came to this conclusion. 

4. Graph your results from both labs. The first graph should be a double line graph with “mass on cart” on the x-axis and “distance 

traveled” on the y-axis. You will have one line showing the ramp car’s data, and one showing the resting car’s data. Your second 

graph should be a double line graph. 

Lab #21:Newton’s 3rd Law: Tug of War 

In this lab, you will continue to investigate Newton’s 3 rd Law by playing a small rubber band tug of war at your 

lab station. 

Procedure 

1. Make sure that you have 2 force sensors plugged into the Lab Pro box. Click collect and push and pull gently on the hooks for 

the force sensor. Get a sense for which sensor gives which color on the graph, and what causes positive and negative graphs. 

2. Attach a rubber band to the hook of each force 

sensor. 

3. Prediction: Put the force sensor down and consider 

the following situation: Suppose that 2 force sensors 

were connected to a single rubber band. If one 

person pulled their force sensor while the other 

person simply stood still, what would the resulting 

graph look like? Pretend that the graph to the right 

shows what the puller’s graph will look like. What 

will the other person’s graph look like? Sketch it on 

this graph. 

4. Connect both force sensors to a single rubber 

band. Make sure the rubber band has no tension 

on it. Click “Collect” and have one person pull and 

the other person stay still. Sketch the resulting 

graph to the right. 




5. Reverse roles: the puller becomes a holder and the 

holder becomes a puller. No need to switch sensors. 

Record your graph to the right. 

6. Have both people pull. Record your graph to the right. 

7. Attach one force sensor to a ring stand as shown. 

Connect the other force sensor by rubber band to the 

one on the ring stand. Have someone securely hold the 

ring stand in place. Repeat the previous activity. 

Questions 

1. Complete the following statement and use the words 

“magnitude” (size) and “direction” in your response. 

Whenever one object exerts a force on a second object, the second exerts a force on the first that is: 

2. So in a real tug-of-war, Newton’s 3 rd Law says that as team one pulls on team two, that team two pulls back with an equal and 

opposite force on the team one. Explain how this could be with writing and diagrams. 

3. If #2 is true, how can anyone ever win at tug of war? Draw a stick figure that represents a tug of war participant. Complete a 

force diagram for this person. What force allows a tug of war participant to win? 

Ready to turn your packet in? You should have all questions completed in this packet (25 pts.). You should have attached to this 

packet: 

� Questions for labs 14-21 (25 pts.) 

� Graphs that you made for labs 19-20 (10 pts.) 

� Graph printed from lab 18 (5 pts.)

Lab #14: Sudden Stops Hurt-Newton's First Law - NNM-Science

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