Motion Lab .
(ANSWERS)
Data Table:
Distance vs. Time for Hot Wheels Car (SAMPLE DATA)
Trial #1
Run #1
Run #2
Run #3
Run #4
Average:
Trial #2
Run #1
Run #2
Run #3
Run #4
Average:
Trial #3
Run #1
Run #2
Run #3
Run #4
Average:
Formulas:
Speed = Distance/Time
1 Book at the end
Distance (cm)
Time (sec.)
190
.70
190
.74
190
.80
190
.76
190 cm
.75 sec.
2 Books at the end
Distance (cm)
Time (sec.)
190
.88
190
.91
190
.90
190
.95
190 cm
.91.
3 Books at the end
Distance (cm)
Time (sec.)
190
.99
190
1.09
190
1.10
190
.98
190 cm
1.04 sec.
or
Average Speed = Df - Di
Tf - Ti
s=d/t
s=d/t
s=d/t
190 cm/.75 sec = 253 cm/s
190 cm/.91 sec = 209 cm/s
190 cm/1.04 sec = 183 cm/s
Calculations:
Trial #1 (One Book):
Trial #2 (Two Books):
Trial #3 (Three Books):
Experimental Design
190 cm
.75 sec
190 cm
.91 sec
190 cm
1.04 sec
253 cm/s
209 cm/s
183 cm/s
Graph:
Distance vs. Time Graph (Average Speed of Hot Wheels)
200
253 cm/s
209 cm/s
183 cm/s
180
160
140
120
Distance 100
(cm)
80
60
KEY (Sample Only)
40
1 Book
2 Books
3 Books
20
0
0
.1
.2
.3
.4
.5
.6
.7
.8
.9
1.0
1.1
Time (seconds)
POST LAB QUESTIONS:
1. List three things that are causing the car to accelerate? (Hint: acceleration is change in velocity)
Gravity, the launcher, friction with track or table, you hands, the book or wall it hits.
2. Where was the acceleration of the car the greatest? (Think about what is causing it to accelerate) Right as it is
being launched from the launcher or at the end of the track if it hits something and stops quickly.
3. Is the speed of the car constant or does it changes as it goes down the track? Explain how you know. The speed
is changing. It started at 0 cm/s and then was launched to over 200 cm/s. At the end of the track it slows
down when it hits the finish line or it falls off the track or
4. Are the velocity and the speed of the car the same in this experiment? Explain your answer in a complete
sentence. Yes and No. They are the same in terms of magnitude (example: 50 cm/s would be the speed and
the velocity). The difference where they are not the same is that the velocity would be 50 cm/s north or south
or east or west. Velocity also has information about the direction the car is moving.
5. What force is causing the car to accelerate down the track? The launcher Are there any other forces acting on the
car to cause it to accelerate/decelerate? Gravity (if track is not perfectly level), the track (especially if curved),
friction from the track, the plastic container or the wall it hits, and you.
6. In the mountains you will sometimes see a sign that says, “Watch Downhill Speed”. What does this mean in terms
of acceleration and the motion we have studied? As you go downhill gravity causes the car to accelerate. If the
downhill is really steep (large slope) it will cause the car to accelerate faster and faster. The driver will try
and use the brakes to control the speed so they don’t go flying off a cliff. The concern is that drivers will
take turns too fast and loose control of their car. A secondary concern is that the brakes will heat up and
become less efficient in stopping the vehicle due to the increase friction and decrease efficiency due to the
heat the brakes will experience from working against gravity and a speeding car with a lot of momentum.
7. What two things could you do to increase the momentum of the car? Add more mass or more speed (velocity).
8. List 3 things you could have used as a reference point (frame of reference) for this lab? The table, track other
car, launcher, books, ruler, partner, finish line, etc.
9. How do you know the cars are in motion? The cars are seen passing a reference point (like the ones listed in
question # 8). You can also measure the change in position (distance) over a specific amount of time.
10. What is/are the variables in the experiment you conducted? (Answers will vary): the cars, lane, books, etc.